The redox potential of selenocystine in unconstrained cyclic peptides - Besse, Dörthe; Siedler, Frank; Diercks, Tammo; Kessler, Horst; Moroder, Luis (Angew. Chem. Int. Ed., 1997)
The following values have no corresponding Zotero field: number: 8 publisher: Hüthig & Wepf Verlag
Keywords: peptides; selenium; redox chemistry

Hydroxylamine-induced cleavage of the asparaginyl-glycine motif in the production of recombinant proteins: the case of insulin-like growth factor I - Antorini, M.; Breme, U.; Caccia, P.; Grassi, C.; Lebrun, S.; Orsini, G.; Taylor, G.; Valsasina, B.; Marengo, E.; Todeschini, R.; Andersson, C.; Gellerfors, P.; et al. (Protein Expr. Purif., 1997)
Hydroxylamine-induced cleavage at the asparaginyl-glycine dipeptide site inserted between the two moieties of recombinant fusion proteins has been used at both the analytical and the preparative scale to obtain the mature protein. In this study a model protein containing a fusion precursor of insulin-like growth factor I was used to investigate the influence of the operating conditions on the cleavage reaction and the formation of undesired side products such as hydroxamate and deamidated analogs. Moreover, the stability of the cleavage site toward deamidation was examined and a chemometric study performed to define the effect of the reaction conditions on the cleavage yield and on the formation of side products.
Journal Article United States
The following values have no corresponding Zotero field: auth-address: Pharmacia & Upjohn, Nerviano, Italy. alt-title: Protein expression and purification number: 1 accession-num: 9325149
Keywords: Amino Acid Sequence; Humans; Hydrogen-Ion Concentration; Molecular Sequence Data; Hydrolysis; Protein Folding; Isoelectric Point; Peptide Mapping; Fermentation; Dipeptides/metabolism; Hydroxamic Acids/metabolism; Hydroxylamine/*pharmacology; Insulin-Like Growth Factor I/*biosynthesis/isolation & purification; Methionine/metabolism; Recombinant Fusion Proteins/biosynthesis/isolation & purification; Spectrometry, Mass, Secondary Ion; Thiosulfates/metabolism

Polyether catalysis of ester aminolysis – A computational and experimental study - Zipse, Hendrik; Wang, Li-Hsing; Houk, Kendall N. (Liebigs Ann., 1996)
Model systems for the reaction of amines with esters were investigated with ab initio methods. Ammonia and methylamine were used as models for primary amines, and formic acid, methyl acetate, phenyl acetate, and p-nitrophenyl acetate were chosen to represent typical esters. Geometry optimizations were performed for all systems with the HF/6–31G** method, and relative energies were evaluated by using MP2/6–31G** single-point energies. The lowest barriers are found for the reaction of methylamine with p-nitrophenyl acetate. Reaction occurs in this case according to a direct displacement pathway, in which all bond formation and breaking occurs in a single step. Complexation of the transition structures by dimethyl ether or dimethoxyethane leads to much the same changes as observed for variation of the leaving group. Based on the ab initio data a force field for the calculation of transition state-catalyst complexation was developed. This force field as well as ground state complexation energies were employed to predict catalytic activities for a number of polyethers, polyalcohols, and pyrans, which in part, were also investigated experimentally.
1099-0690
The following values have no corresponding Zotero field: number: 10 publisher: WILEY-VCH Verlag
Keywords: Catalysis; Esters; Aminolysis; Calculations, ab initio

Bifunctional catalysis of ester aminolysis – A computational and experimental study - Wang, Li-Hsing; Zipse, Hendrik (Liebigs Ann., 1996)
Various pathways for the reaction of methylamine with methyl acetate catalyzed by 2(1H)-pyridone have been investigated at the Becke3LYP/6–31G**/HF/6–31G** level of theory. The most favorable pathway consists of a one-step reaction, in which all bond-forming and -breaking processes occur in concert. These modeling studies also show the pyridone to function as an acid, which led to the investigation of several substituted pyridones. 4-Cyano-, 3-cyano-6-methyl-, and 3-cyano-2(1H)-pyridone have indeed been shown to provide better catalysis in the ester aminolysis reaction by ab initio modeling at the Becke3LYP/6–31G**/HF/3–21G level. In order to verify the theoretical results, the catalytic activities of various substituted 2-pyridones in the reaction of n-butylamine with p-nitrophenyl acetate in chlorobenzene solution have been determined. The observed catalytic rate constants are indeed in agreement with the theoretical predictions. Other catalyst characteristics such as solubility and state of aggregation are, however, also of paramount importance in this reaction.
1099-0690
The following values have no corresponding Zotero field: number: 10 publisher: WILEY-VCH Verlag
Keywords: Catalysis; Esters; Aminolysis; Calculations, ab initio; Pyridones

Improved refolding of an immobilized fusion protein - Stempfer, G.; Holl-Neugebauer, B.; Rudolph, R. (Nat. Biotechnol., 1996)
Fusion proteins of monomeric alpha-glucosidase from Saccharomyces cerevisiae containing N- or C-terminal hexa-arginie peptides were expressed in the cytosol of Escherichia coli in soluble form. The polycationic peptide moieties allow noncovalent binding of the denatured fusion proteins to a polyanionic solid support. Upon removal of the denaturant, refolding of the matrix-bound protein can proceed without perturbation by aggregation. However, nonspecific interactions of the denatured polypeptide, or of folding intermediates, with the matrix cause a drastic decrease in renaturation under suboptimal folding conditions. At low salt concentrations, ionic interactions of the refolding polypeptide with the matrix result in lower yields of renaturation. At higher salt concentrations, renaturation is prevented by hydrophobic interactions with the matrix. Apart from ionic strength, renaturation of the denatured matrix-bound fusion protein must be optimized with respect to pH, temperature, cosolvents, and matrix material used. Under optimum conditions, immobilized alpha-glucosidase can be renatured with a high yield at protein concentrations up to 5 mg/ml, whereas folding of the wild-type enzyme in solution is feasible only at an extremely low protein concentration (15 micrograms/ml). Thus, folding of the immobilized alpha-glucosidase allows an extremely high yield of the renaturated model protein. The technology should be applicable to other proteins that tend to aggregate during refolding.
Stempfer, G Holl-Neugebauer, B Rudolph, R Comparative Study United states Nature biotechnology Nat Biotechnol. 1996 Mar;14(3):329-34.
The following values have no corresponding Zotero field: auth-address: Boehringer Mannheim Therapeutics, Penzberg, Germany. number: 3 edition: 1996/03/01 accession-num: 9630895
Keywords: Protein Conformation; Temperature; Protein Folding; Protein Denaturation; Escherichia coli/genetics; Osmolar Concentration; alpha-Glucosidases/chemistry/genetics; Biotechnology; Enzymes, Immobilized; Recombinant Fusion Proteins/*chemistry/genetics; Saccharomyces cerevisiae/enzymology/genetics; Sodium Chloride

Heparin induces dimerization and confers proliferative activity onto the hepatocyte growth factor antagonists NK1 and NK2 - Schwall, R. H.; Chang, L. Y.; Godowski, P. J.; Kahn, D. W.; Hillan, K. J.; Bauer, K. D.; Zioncheck, T. F. (J. Cell Biol., 1996)
Hepatocyte growth factor (HGF) is a potent epithelial mitogen whose actions are mediated through its receptor, the proto-oncogene c-Met. Two truncated variants of HGF known as NK1 and NK2 have been reported to be competitive inhibitors of HGF binding to c-Met, and to function as HGF antagonists (Lokker, N.A., and P.J. Godowski. 1993. J. Biol. Chem. 268: 17145-17150; Chan, A.M., J.S. Rubin, D.P. Bottaro, D.W. Hirschfield, M. Chedid, and S.A. Aaronson. 1991. Science (Wash. DC). 254:1382-1387). We show here, however, that NK1 acts as a partial agonist in mink lung cells. Interestingly, NK1, which is an HGF antagonist in hepatocytes in normal conditions, was converted to a partial agonist by adding heparin to the culture medium. The interaction of NK1 and heparin was further studied in BaF3 cells, which express little or no cell surface heparan sulfate proteoglycans. In BaF3 cells transfected with a plasmid encoding human c-Met, heparin and NK1 synergized to stimulate DNA synthesis and cell proliferation. There was no effect of heparin on the IL-3 sensitivity of BaF3-hMet cells, and no effect of NK1 plus heparin in control BaF3 cells, indicating that the response was specific and mediated through c-Met. The naturally occurring HGF splice variant NK2 also stimulated DNA synthesis in mink lung cells and exerted a heparin-dependent effect on BaF3-hMet cells, but not on BaF3-neo cells. The activating effect of heparin was mimicked by a variety of sulfated glycosaminoglycans. Mechanistic studies revealed that heparin increased the binding of NK1 to BaF3-hMet cells, stabilized NK1, and induced dimerization of NK1. Based on these studies, we propose that the normal agonist activity of NK1 and NK2 in mink lung cells is due to an activating interaction with an endogenous glycosaminoglycan. Consistent with that model, a large portion of the NK1 binding to mink lung cells could be blocked by heparin. Moreover, a preparation of glycosaminoglycans from the surface of mink lung cells induced dimerization of NK1. These data show that the activity of NK1 and NK2 can be modulated by heparin and other related glycosaminoglycans to induce proliferation in cells expressing c-Met.
0021-9525 (Print) 0021-9525 (Linking) Comparative Study Journal Article
The following values have no corresponding Zotero field: auth-address: Genentech, Inc., South San Francisco, California 94080-4990, USA. rhs@gene.com number: 3 accession-num: 8636243
Keywords: Animals; Humans; Sensitivity and Specificity; Rats; DNA/biosynthesis; Cell Division/drug effects; Female; Glycosaminoglycans/pharmacology; Heparin/*pharmacology; Hepatocyte Growth Factor/*antagonists & inhibitors/metabolism; Liver/*cytology; Lung/cytology; Mink; Protein Binding/physiology; Proto-Oncogene Proteins c-met; Rats, Sprague-Dawley; Receptor Protein-Tyrosine Kinases/physiology; Receptors, Neurokinin-1/agonists/metabolism; Receptors, Neurokinin-2/agonists/metabolism

Identification of D-peptide ligands through mirror-image phage display - Schumacher, T. N.; Mayr, L. M.; Minor, D. L.; Milhollen, M. A.; Burgess, M. W.; Kim, P. S. (Science, 1996)
Genetically encoded libraries of peptides and oligonucleotides are well suited for the identification of ligands for many macromolecules. A major drawback of these techniques is that the resultant ligands are subject to degradation by naturally occurring enzymes. Here, a method is described that uses a biologically encoded library for the identification of D-peptide ligands, which should be resistant to proteolytic degradation. In this approach, a protein is synthesized in the D-amino acid configuration and used to select peptides from a phage display library expressing random L-amino acid peptides. For reasons of symmetry, the mirror images of these phage-displayed peptides interact with the target protein of the natural handedness. The value of this approach was demonstrated by the identification of a cyclic D-peptide that interacts with the Src homology 3 domain of c- SRC. Nuclear magnetic resonance studies indicate that the binding site for this D-peptide partially overlaps the site for the physiological ligands of this domain.
Journal Article Research Support, Non-U.S. Gov't United states
The following values have no corresponding Zotero field: auth-address: Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge MA 02142, USA. alt-title: Science (New York, N.Y number: 5257 accession-num: 8596952
Keywords: Amino Acid Sequence; Animals; Stereoisomerism; Molecular Sequence Data; Base Sequence; Magnetic Resonance Spectroscopy; Binding Sites; Ligands; *src Homology Domains; Chickens; Cloning, Molecular; Bacteriophages; Gene Library; Peptides, Cyclic/chemistry/genetics/*metabolism; Peptides/chemistry/genetics/*metabolism; Proto-Oncogene Proteins pp60(c-src)/chemistry/*metabolism

Acyl disulfide-mediated intramolecular acylation for orthogonal coupling between unprotected peptide segments. Mechanism and application - Liu, Chuan-Fa; Rao, Chang; Tam, James P. (Tetrahedron Lett., 1996)
A highly efficient orthogonal coupling approach for peptide bond formation using unprotected peptide segments was described. The key element of this approach consisted of capturing an Npys modified N-Cys side-chain thiol of the amino segment with a CÎ±-thiocarboxylic acid of the acyl segment to form an acyl disulfide which undergoes rapid intramolecular acylation to generate an amide bond. A final product with a native Cys residue at the ligation site was obtained after a thiolytic reduction step.
0040-4039 doi: 10.1016/0040-4039(95)02394-1
The following values have no corresponding Zotero field: number: 7

A self-replicating peptide - Lee, D. H.; Granja, J. R.; Martinez, J. A.; Severin, K.; Ghadiri, M. R. (Nature, 1996)
The production of amino acids and their condensation to polypeptides under plausibly prebiotic conditions have long been known. But despite the central importance of molecular self-replication in the origin of life, the feasibility of peptide self-replication has not been established experimentally. Here we report an example of a self-replicating peptide. We show that a 32-residue alpha-helical peptide based on the leucine-zipper domain of the yeast transcription factor GCN4 can act autocatalytically in templating its own synthesis by accelerating the thioester-promoted amide-bond condensation of 15- and 17-residue fragments in neutral, dilute aqueous solutions. The self-replication process displays parabolic growth pattern with the initial rates of product formation correlating with the square-foot of initial template concentration.
Journal Article Research Support, Non-U.S. Gov't England
The following values have no corresponding Zotero field: auth-address: Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA. alt-title: Nature number: 6591 accession-num: 8700225
Keywords: Amino Acid Sequence; Catalysis; Molecular Sequence Data; Peptides/chemistry; Templates, Genetic; *Peptide Biosynthesis; Fungal Proteins/*chemistry; Protein Kinases/*chemistry; *Saccharomyces cerevisiae Proteins; *DNA-Binding Proteins; Leucine Zippers; Transcription Factors/*chemistry

Catalysis of acyl transfer from amides to thiolate nucleophiles: The reaction of a distorted anilide with thioglycolic acid and ethyl 2-mercaptoacetate - Kellogg, B. A.; Neverov, A. A.; Aman, Ahmed M.; Brown, R. S. (J. Am. Chem. Soc., 1996)
The following values have no corresponding Zotero field: number: 44 publisher: American Chemical Society

Synthesis and liposome-formation of a thermostable lipid bearing cell adhesion peptide sequence - Hojo, Hironobu; Kojima, Takashi; Yamauchi, Kiyoshi; Kinoshita, Masayoshi (Tetrahedron Lett., 1996)
The following values have no corresponding Zotero field: number: 41

The reaction mechanism of the internal thioester in the human complement component C4 - Dodds, Alister W.; Ren, Xiang-Dong; Willis, Antony C.; Law, S. K. Alex (Nature, 1996)
10.1038/379177a0 10.1038/379177a0
The following values have no corresponding Zotero field: number: 6561

Extending the applicability of native chemical ligation - Canne, Lynne E.; Bark, Steven J.; Kent, Stephen B. H. (J. Am. Chem. Soc., 1996)
doi: 10.1021/ja960398s 0002-7863 doi: 10.1021/ja960398s
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

Chemical synthesis and purification of proteins: a methodology - Ball, H. L.; Mascagni, P. (Int. J. Pept. Protein Res., 1996)
Classical stepwise solid-phase peptide synthesis (SPPS) has been used successfully for the synthesis of proteins up to 150 residues in length, although usually with poor yields and homogeneity. The major limitation has been the inability to separate chromatographically similar deletion and truncated impurities from the target sequence. We have developed a highly effective protocol for stepwise SPPS and 'one-step' purification of small proteins. to demonstrate the effectiveness of the methodology we synthesised the 101 residue chaperonin 10 protein from Rattus norvegicus (Rat Cpn 10) using three different chemical protocols. Highly homogeneous Rat Cpn10 was obtained using an optimised synthetic strategy and one-step purification procedure (method C), involving (i) HBTU/HOBt activation, (ii) N-(2-chlorobenzyloxycarbonyloxy)succinimide as capping agent and (iii) the incorporation of a reversible Fmoc-based chromatographic probe, derivatised with a lipophilic group for fast one-step RP purification, to give an overall yield of 9.6%. Analysis by ESI-MS indicated that the product was virtually free of deletion impurities, while RP-HPLC under four different conditions and CZE indicated that the protein was 100 and 84% pure, respectively. The spontaneous folding of Rat Cpn10 into its biologically active form was found to correlate well with the degree of purity as assessed by chromatography, ESI-MS and sequencing, since 29 (A), 55 (B) and 81% (C) of correctly folded heptameric structure was obtained. The degree of homogeneity was also reflected in the ability of purified Rat Cpn10 to facilitate the refolding of yeast enolase.
0367-8377 (Print) 0367-8377 (Linking) Comparative Study Journal Article
The following values have no corresponding Zotero field: auth-address: Department of Peptide Chemistry, Italfarmaco Research Centre, Cinisello Balsamo, Milan, Italy. number: 1 accession-num: 8844261
Keywords: Amino Acid Sequence; Animals; Protein Conformation; Molecular Sequence Data; Protein Folding; Methods; Rats; Chaperonin 10/chemical synthesis/chemistry/isolation & purification; Chromatography, High Pressure Liquid/methods; Chromatography/methods; Peptides/*chemical synthesis/chemistry/*isolation & purification

Activation method to prepare a highly reactive acylsulfonamide "safety-catch" linker for solid-phase synthesis - Backes, Bradley J.; Virgilio, Alex A.; Ellman, Jonathan A. (J. Am. Chem. Soc., 2013)
doi: 10.1021/ja9535165
The following values have no corresponding Zotero field: number: 12 publisher: American Chemical Society

Why protein crystals favour some space-groups over others - Wukovitz, S. W.; Yeates, T. O. (Nat. Struct. Biol., 1995)
One of the most puzzling observations in protein crystallography is that the various space-group symmetries occur with striking non-uniformity. Molecular close-packing has been invoked to explain similar observations for crystals of small organic compounds, but does not appear to be the dominant factor for proteins. Instead, we find that the observed frequencies for both two- and three-dimensional crystals can be explained by an entropic model. Under a requirement for connectivity, the favoured space groups are simply less restrictive than others in that they allow the molecules more rigid-body degrees of freedom and can therefore be realized in a greater number of ways. This result underscores the importance of the nucleation event in crystallization and leads to specific ideas for crystallizing water-soluble and membrane proteins.
Journal Article Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. United states
The following values have no corresponding Zotero field: auth-address: Department of Biomathematics, University of California, Los Angeles 90095-1766, USA. alt-title: Nature structural biology number: 12 accession-num: 8846217
Keywords: Protein Conformation; Crystallography, X-Ray; Proteins/*chemistry/*ultrastructure

The history of peptide chemistry - Wieland, T. (Peptides: Synthesis, Structure, and Applications, 1995)
Keywords: #nosource

Detection of secondary amines on solid phase - Vojkovsky, T. (Pept. Res., 1995)
The detection of secondary amino groups in building blocks attached to solid phase using tetrachlorobenzoquinone (chloranil) was re-examined. A new procedure, about ten times more sensitive than the original method, has been developed. Except for N(p-tolyl)glycine, all secondary amino groups that were examined were detected reliably in a substitution range down to 2.8 micro eq/g. Protected imidazole in His(Trt) did not interfere with the detection method.
The following values have no corresponding Zotero field: auth-address: Marion Merrell Dow Inc., Selectide, Tucson, AZ, USA. number: 4 edition: 1995/07/01 accession-num: 8527877
Vojkovsky, T United states Peptide research Pept Res. 1995 Jul-Aug;8(4):236-7.
Keywords: Chloranil/chemistry; Amines/*analysis; Reproducibility of Results

Chemoselective approaches to the preparation of peptide dendrimers and branched artificial proteins using unprotected peptides as building blocks - Tam, J. P.; Spetzler, J. C. (Biomed. Pept. Proteins Nucleic Acids, 1995)
Peptide dendrimers such as Multiple Antigen Peptides (MAPs) are artificial proteins with branched architectures. They hold promise in biochemical and biomedical applications such as synthetic vaccines, serodiagnostics and intracellular delivery of peptides. We have shown that a new design of MAPs containing lipidated built-in adjuvant can be delivered by oral administration to elicit systemic and mucosal immunoglobulins as well as cytotoxic T-lymphocytes. For synthetic vaccines, it is desirable to obtain highly homogeneous preparations. To provide the precision and chemical unambiguity of this class of artificial proteins, we have devised several chemoselective approaches by thiol and carbonyl chemistries to facilitate their synthesis using unprotected peptide segments as building blocks and ligating them to the core matrix. This paper describes the methods of preparation, comparative studies of stability, and presents results of the preparation of antigens containing preformed multiple disulfides.
1353-8616 (Print) 1353-8616 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S. Review
The following values have no corresponding Zotero field: auth-address: Vanderbilt University Medical Center, Dept. of Microbiology and Immunology, Nashville, TN 37232-2363, USA. number: 3 accession-num: 9346843
Keywords: Sulfhydryl Compounds/*chemistry; Aldehydes/*chemistry; Hydrazones/*chemistry; Oximes/*chemistry; Peptides/*chemistry/immunology; Thiazoles/*chemistry; Vaccines, Synthetic/*chemistry/immunology

Specificity and formation of unusual amino acids of an amide ligation strategy for unprotected peptides - Tam, J. P.; Rao, C.; Liu, C. F.; Shao, J. (Int. J. Pept. Protein Res., 1995)
An important step in the recently developed ligation strategy known as domain ligation strategy to link unprotected peptide segments without activation is the ring formation between the C-terminal ester aldehyde and the N-terminal amino acid bearing a beta-thiol or beta-hydroxide. A new method was developed to define the specificity of this reaction using a dye-labeled alanyl ester aldehyde to react with libraries of 400 dipeptides which contained all dipeptide combinations of the 20 genetically coded amino acids. Three different ester aldehydes of the dye-labeled alanine: alpha-formylmethyl (FM), beta-formylethyl (FE), and beta,beta,beta-dimethyl and formylethyl esters (DFE), were examined. The DFE ester was overly hindered and reacted with N-terminal Cys dipeptides (Cys-X). Interestingly, it also reacted slowly with the sequences of X-Gly where Gly was the second amino acid and the X-Gly amide bond participated in the ring formation. Although the FE ester reacted similarly as the FM ester in the ring formation, the subsequent O,N-acyl transfer was at least 30-fold slower than those of the FM-ester. The FM alpha-formyl methyl ester was the most suitable ester and was reactive with dipeptides of six N-terminal amino acids: Cys, Thr, Trp, Ser, His and Asn. The order and extent of their reactivity were highly dependent on pH, solvent and neighboring participation by the adjacent amino acid. In general, they could be divided into three categories. (1) N-Terminal Cys and Thr were the most reactive.(ABSTRACT TRUNCATED AT 250 WORDS)
Tam, J P Rao, C Liu, C F Shao, J Denmark Int J Pept Protein Res. 1995 Mar;45(3):209-16.
The following values have no corresponding Zotero field: auth-address: Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA. alt-title: International journal of peptide and protein research number: 3 edition: 1995/03/01 accession-num: 7775013
Keywords: Amides/*chemistry; Amino Acids/*chemistry; Peptides/*chemical synthesis; Azo Compounds

Peptide synthesis using unprotected peptides through orthogonal coupling methods - Tam, J. P.; Lu, Y. A.; Liu, C. F.; Shao, J. (Proc. Natl. Acad. Sci. U. S. A., 1995)
We describe an approach to the synthesis of peptides from segments bearing no protecting groups through an orthogonal coupling method to capture the acyl segment as a thioester that then undergoes an intramolecular acyl transfer to the amine component with formation of a peptide bond. Two orthogonal coupling methods to give the covalent ester intermediate were achieved by either a thiol-thioester exchange mediated by a trialkylphosphine and an alkylthiol or a thioesterification by C alpha-thiocarboxylic acid reacting with a beta-bromo amino acid. With this approach, unprotected segments ranging from 4 to 37 residues were coupled to aqueous solution to give free peptides up to 54 residues long with high efficiency.
0027-8424 (Print) 0027-8424 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S.
The following values have no corresponding Zotero field: auth-address: Department of Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232-2363, USA. number: 26 accession-num: 8618926
Keywords: Amino Acid Sequence; Hydrogen-Ion Concentration; Peptides/*chemical synthesis/chemistry; Molecular Sequence Data; Chromatography, High Pressure Liquid; Acylation; Solutions; Indicators and Reagents; Oligopeptides/chemical synthesis/chemistry; Cysteine; Phosphines; Sulfhydryl Compounds

Unprotected peptides as building blocks for branched peptides and peptide dendrimers - Spetzler, J. C.; Tam, J. P. (Int. J. Pept. Protein Res., 1995)
We describe two new site-specific ligation methods for preparing branched peptide dendrimers such as multiple antigen peptide (MAP). Both methods are based on the general approach of exploiting the specific reaction between a weak base and an aldehyde under acidic conditions so that unprotected peptides can be used as building blocks. A weak base such as benzoyl hydrazine or 1,2-amino thiol of cysteine was attached to the N-terminal of an unprotected peptide as nucleophile to react with the alkyl aldehyde on the core matrix of MAP to form a stable hydrazone linkage or a five-membered thiazolidine ring, respectively. Two synthetic peptides rich in basic amino acids such as lysine and arginine were used as models in the ligation reactions in solution to give peptide dendrimers containing four or eight copies of peptide immunogens. The resulting macromolecules with the MW ranging from 5 to 16 kDa were unambiguously characterized by laser-desorption mass spectrometry. Furthermore, we also optimized the conditions of these ligation reactions using elevated temperature and a water-miscible organic co-solvent to give a combination of rate enhancement about 10 fold. These optimizations allowed the ligation reactions to be completed in < 4 h instead of 2-3 days. Our ligation approach also has the advantages of flexibility so that peptides can be attached through the amino or carboxyl terminus to the core matrix. The phenyl hydrazone linkage and the five-membered ring were found to be stable at physiological pH suitable for immunization. Thus our results provide two practical and useful methods for the synthesis of macromolecular peptide dendrimers for vaccines, artificial proteins, and enzymes.
0367-8377 (Print) 0367-8377 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S.
The following values have no corresponding Zotero field: auth-address: Department of Microbiology and Immunology, Vanderbilt University Medical Center North, Nashville, Tennessee, USA. number: 1 accession-num: 7775011
Keywords: Amino Acid Sequence; Protein Conformation; Molecular Structure; Molecular Sequence Data; Drug Stability; Thiazoles/chemistry; Peptide Fragments/chemical synthesis; Peptides/*chemistry/immunology; Aldehydes; Alkalies; Antigens/*chemistry; Hydrazones/chemical synthesis

A study of the use of NH4I for the reduction of methionine sulfoxide in peptides containing cysteine and cystine - Nicolas, Ernesto; Vilaseca, Marta; Giralt, Ernest (Tetrahedron, 1995)
Methionine sulfoxide reduction by NH4I has been studied in some disulfide containing peptides. In general, this reagent has proved to be effective in neat TFA at 0Â°C, with the obtention of the unprotected peptides in more than 99% yields and without reduction of the disulfide bridge bond. The use of Me2S as an additive resulted in faster reactions and disulfide scrambling was not observed. Whereas the Acm group proved to be stable to the reaction conditions, unprotected cysteine containing peptides afforded the corresponding parallel dimers.
0040-4020
The following values have no corresponding Zotero field: number: 19

Cell density control of staphylococcal virulence mediated by an octapeptide pheromone - Ji, G.; Beavis, R. C.; Novick, R. P. (Proc. Natl. Acad. Sci. U. S. A., 1995)
Some bacterial pathogens elaborate and secrete virulence factors in response to environmental signals, others in response to a specific host product, and still others in response to no discernible cue. In this study, we have demonstrated that the synthesis of Staphylococcus aureus virulence factors is controlled by a density-sensing system that utilizes an octapeptide produced by the organism itself. The octapeptide activates expression of the agr locus, a global regulator of the virulence response. This response involves the reciprocal regulation of genes encoding surface proteins and those encoding secreted virulence factors. As cells enter the postexponential phase, surface protein genes are repressed by agr and secretory protein genes are subsequently activated. The intracellular agr effector is a regulatory RNA, RNAIII, whose transcription is activated by an agr-encoded signal transduction system for which the octapeptide is the ligand.
R01-A130138/PHS HHS/United States Comparative Study Journal Article Research Support, U.S. Gov't, P.H.S. United States
The following values have no corresponding Zotero field: auth-address: Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine, New York University Medical Center, New York 10016, USA. alt-title: Proceedings of the National Academy of Sciences of the United States of America number: 26 accession-num: 8618843
Keywords: Amino Acid Sequence; Sequence Homology, Amino Acid; Molecular Sequence Data; Gene Expression Regulation, Bacterial; *Trans-Activators; Bacillus subtilis/genetics; Bacterial Proteins/*biosynthesis/metabolism; Genotype; Operon; Pheromones/biosynthesis/chemistry/*physiology; Plasmids; RNA, Antisense/biosynthesis/metabolism; RNA, Bacterial/biosynthesis/metabolism; Species Specificity; Staphylococcus aureus/genetics/*growth & development/*pathogenicity; Transcription Factors/*biosynthesis/metabolism; Transcription, Genetic; Virulence/genetics/physiology

A novel 4-aminobenzyl ester-based carboxy-protecting group for synthesis of atypical peptides by Fmoc-But solid-phase chemistry - Chan, Weng C.; Bycroft, Barrie W.; Evans, David J.; White, Peter D. (J. Chem. Soc., Chem. Commun., 1995)
4{-[1-(4, 4-Dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]amino}benzyl ester (ODmab) is a new carboxy-protecting group that is based on the safety-catch principle and can be used orthogonally with Fmoc-Bupeptide chemistry, but is completely removable with 2%/ hydrazine[middle dot]HO-DMF at room temperature within minutes.
0022-4936 10.1039/C39950002209
The following values have no corresponding Zotero field: number: 21 publisher: The Royal Society of Chemistry

A general method for the synthesis of thioester resin linkers for use in the solid phase synthesis of peptide-a-thioacids - Canne, Lynne E.; Walker, Sharon M.; Kent, Stephen B. H. (Tetrahedron Lett., 1995)
The following values have no corresponding Zotero field: number: 8

Affinity purification of 101 residue rat cpn10 using a reversible biotinylated probe - Ball, H. L.; Bertolini, G.; Mascagni, P. (J. Pept. Sci., 1995)
The purification of large synthetic peptides using conventional separation techniques often results in poor yields and homogeneity due to the accumulation of chromatographically similar deletion and truncated impurities. We have developed a highly effective synthetic strategy and one-step purification procedure that is based on (i) the application of single coupling using HBTU/HOBt activation to reduce incomplete couplings, (ii) the use of N-(2-chlorobenzyloxycarbonyloxy)succinimide as a capping agent to terminate deletion sequences and (iii) the N-terminal derivatization of the complete peptidyl-resin with a reversible Fmoc-based chromatographic probe possessing enhanced physico-chemical properties (i.e. hydrophobicity, charge or affinity label). We report the application of a biotinylated probe, activated as the succinimidyl carbonate, for the purification of a 101 residue chaperonin protein from Rattus norvegicus (rat cpn10), previously synthesized using an optimized synthetic protocol. Biotinylated rat cpn10 was separated from underivatized impurities on an immobilized monomeric avidin column. Free rat cpn10 was released from avidin-agarose column with 5% aqueous triethylamine and after desalting by RP-HPLC gave 9.9% recovery. Characterization and assessment of homogeneity was achieved using ESI-MS, CZE and RP-HPLC.
1075-2617 (Print) 1075-2617 (Linking) Journal Article
The following values have no corresponding Zotero field: auth-address: Italfarmaco Research Centre, Milan, Italy. number: 5 accession-num: 9223007
Keywords: Animals; Chromatography, High Pressure Liquid; Rats; Indicators and Reagents; Molecular Probes; Molecular Weight; Avidin; Biotin; Chaperonin 10/chemical synthesis/chemistry/*isolation & purification; Chromatography, Affinity/*methods

Total chemical synthesis of a folded b-sandwich protein domain: An analog of the tenth fibronectin type 3 module - Williams, Michael J.; Muir, Tom W.; Ginsberg, Mark H.; Kent, Stephen B. H. (J. Am. Chem. Soc., 2014)
doi: 10.1021/ja00102a060
The following values have no corresponding Zotero field: number: 23 publisher: American Chemical Society

Molecular interactions in solution: An overview of methods based on continuous distributions of the solvent - Tomasi, Jacopo; Persico, Maurizio (Chem. Rev., 1994)
doi: 10.1021/cr00031a013
The following values have no corresponding Zotero field: number: 7 publisher: American Chemical Society

Bent hydrogen bonds and proton transfers - Scheiner, Steve (Acc. Chem. Res., 1994)
doi: 10.1021/ar00048a003 0001-4842 doi: 10.1021/ar00048a003
The following values have no corresponding Zotero field: number: 12 publisher: American Chemical Society

Water-assisted reactions in aqueous solution - Rivail, Jean-Louis; Antonczak, Serge; Chipot, Christophe; Ruiz-López, Manuel F.; Gorb, Leonid G. (Structure and Reactivity in Aqueous Solution, 1994)
09/29 2017/02/22 0 doi:10.1021/bk-1994-0568.ch011 doi:10.1021/bk-1994-0568.ch011 0-8412-2980-5

Carboxyl-protecting groups convertible into activating groups. Carbamates of o-aminoanilides are precursors of reactive N-acylureas - Pascal, Robert; Chauvey, Denis; Sola, Régine (Tetrahedron Lett., 1994)
Selected carbamates of o-aminoanilides of amino acid derivatives are stable under neutral and acidic aqueous conditions but undergo a quantitative base-catalysed intramolecular conversion into an 1-acylbenzimidazolin-2-one. The pH-rate profiles for this reaction and for the subsequent hydrolysis of the N-acylurea were established. The N-acylurea displays a hydrolytic reactivity reaching that of active esters and is shown to acylate leucine methyl ester.
The following values have no corresponding Zotero field: number: 34

Mutational analysis and molecular modeling of the N-terminal kringle-containing domain of hepatocyte growth factor identifies amino acid side chains important for interaction with the c-Met receptor - Lokker, N. A.; Presta, L. G.; Godowski, P. J. (Protein Eng., 1994)
The hepatocyte growth factor receptor (HGFr) transduces a wide range of biological signals, including mitogenesis, motogenesis and morphogenesis. We recently localized a region within the N-terminal 175 amino acids of hepatocyte growth factor (HGF), termed HGF/NK1, that is necessary and sufficient for binding to the HGFr. HGF/NK1 contains an as-yet structurally undefined N-terminal region followed by the first of four HGF kringles. We have used a combination of molecular modeling and mutagenesis to dissect the function of this region of HGF. Two mutation-sensitive patches on the proposed surface regions of HGF kringle one (K1) were identified. The first patch consists of residues E159, S161, E195 and R197, all of which are predicted to be close to each other in the tertiary structure of K1. The second patch, lying on the opposite side of the kringle, consists of residues D171 and Q173. Mutational analysis of the N-terminal region of HGF identified residue D117 which also appeared to influence receptor binding. We also investigated the properties of a naturally occurring HGF variant (delta 5-HGF) that arises from an alternatively spliced transcript and therefore lacks five residues within K1. Our data suggest that in wild-type HGF, F162 is crucial in maintaining the hydrophobic core of the kringle. In delta 5-HGF, the loss of this residue is compensated for by a functional substitution of F162 with Y167, which is predicted to occupy the delta 5-HGF K1 core. Comparison of the models of wild-type and delta 5 kringles reveals that the positions of the presumed receptor binding determinants remain unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
0269-2139 (Print) 0269-2139 (Linking) Comparative Study Journal Article
The following values have no corresponding Zotero field: auth-address: Department of Cell Genetics, Genentech, Inc., South San Francisco, CA 94080. number: 7 accession-num: 7971951
Keywords: Amino Acid Sequence; Animals; Sequence Homology, Amino Acid; Cell Line; Protein Binding; Molecular Sequence Data; *Models, Molecular; Sequence Alignment; Crystallography, X-Ray; *Protein Structure, Tertiary; Binding Sites; Dogs; Signal Transduction; *Computer Simulation; Cricetinae; Kidney; Mutagenesis, Site-Directed; Proto-Oncogene Proteins c-met; *Kringles; CHO Cells; Fibrin/metabolism; Hepatocyte Growth Factor/*metabolism; Receptor Protein-Tyrosine Kinases/*chemistry/metabolism

Peptide segment ligation strategy without use of protecting groups - Liu, C. F.; Tam, J. P. (Proc. Natl. Acad. Sci. U. S. A., 1994)
We describe the concept and the verification of a chemical ligation approach to the synthesis of proteins using peptide segments with no protecting groups and no activation of the C-terminal alpha-carboxyl group. This approach consists of three steps: (i) aldehyde introduction, in which a masked glycolaldehyde ester is linked to the carboxyl terminus of an unprotected peptide by reverse proteolysis; (ii) ring formation, in which the unmasked aldehyde reacts with the N-terminal alpha-amino group of the second unprotected peptide containing either a cysteine or a threonine residue to form a thiazolidine or oxazolidine ring at an acidic pH; and (iii) rearrangement in which O-acyl ester linkage is transferred to N-acyl amide linkage to form a peptide bond with a pseudoproline structure at higher pH. The feasibility of this scheme was verified by a model study on small compounds and its potential was demonstrated by the synthesis of a 50-residue epidermal growth factor-like peptide containing a preformed disulfide bond.
0027-8424 (Print) 0027-8424 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S.
The following values have no corresponding Zotero field: auth-address: Department of Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232-2363. number: 14 accession-num: 8022823
Keywords: Amino Acid Sequence; Proteins/*chemical synthesis/chemistry; Peptides/*chemical synthesis/chemistry; Molecular Sequence Data; Mass Spectrometry; Esters; Indicators and Reagents; Molecular Weight; Cysteine; Disulfides; Epidermal Growth Factor/*chemical synthesis; Threonine

Concerted or stepwise mechanisms for acyl transfer reactions of p-nitrophenyl acetate? Transition state structures from isotope effects - Hengge, Alvan C.; Hess, Robert A. (J. Am. Chem. Soc., 1994)
doi: 10.1021/ja00104a007 0002-7863 doi: 10.1021/ja00104a007
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

A procedure for quantitative determination of tris(2-carboxyethyl)phosphine, an odorless reducing agent more stable and effective than dithiothreitol - Han, J. C.; Han, G. Y. (Anal. Biochem., 1994)
The concentration of tris(2-carboxyethyl)phosphine (TCEP) can be conveniently determined by measuring the amount of 2-nitro-5-thiobenzoate (NTB) formed after reaction with 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB). This method utilizes the fact that TCEP reduces DTNB rapidly and stoichiometrically to generate two equivalents of NTB which, in its anionic form, has a molar extinction coefficient of 14,150 M−1 cm−1 at 412 nm. This method is sensitive enough to detect the concentration of TCEP in the micromolar range and has proven useful in monitoring the stability or oxidation of TCEP under various conditions. TCEP is not only very stable in acidic solutions, but unlike dithiothreitol (DTT) which readily oxidizes above pH 7.5, it is also highly stable in basic solutions. The rates of reduction of DTNB by TCEP and DTT are compared in the pH range 6-9. Below pH 8, TCEP is significantly more effective than DTT in reducing this disulfide. The rates of reduction of 2,2′-dithiodipyridine (2,2′-DTDP) by TCEP and DTT are compared in the pH range 1.5-8.5. Unlike DTT which is totally inactive at pH 1.5, TCEP is still capable of reducing 2,2′-DTDP effectively at this pH. Thus, if TCEP and thiols are simultaneously present, the concentration of TCEP can be selectively determined by using 2,2′-DTDP at very low pH.
0003-2697
The following values have no corresponding Zotero field: number: 1

Methods for removing the Fmoc group - Fields, G. B. (Methods Mol. Biol., 1994)
1064-3745 (Print) 1064-3745 (Linking) Journal Article Review
The following values have no corresponding Zotero field: auth-address: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis. accession-num: 7894598
Keywords: Peptides/*chemical synthesis/chemistry; Glycopeptides/chemical synthesis/chemistry; Solutions; Indicators and Reagents; Molecular Biology/*methods; Fluorenes/chemistry/*isolation & purification; Spectrophotometry

Synthesis of proteins by native chemical ligation - Dawson, P. E.; Muir, T. W.; Clark-Lewis, I.; Kent, S. B. H. (Science, 1994)
A simple technique has been devised that allows the direct synthesis of native backbone proteins of moderate size. Chemoselective reaction of two unprotected peptide segments gives an initial thioester-linked species. Spontaneous rearrangement of this transient intermediate yields a full-length product with a native peptide bond at the ligation site. The utility of native chemical ligation was demonstrated by the one-step preparation of a cytokine containing multiple disulfides. The polypeptide ligation product was folded and oxidized to form the native disulfide-containing protein molecule. Native chemical ligation is an important step toward the general application of chemistry to proteins.
0036-8075 (Print) 0036-8075 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S.
The following values have no corresponding Zotero field: auth-address: Scripps Research Institute, La Jolla, CA 92037. number: 5186 accession-num: 7973629
Keywords: Amino Acid Sequence; Humans; Protein Conformation; Proteins/*chemical synthesis/chemistry; Molecular Sequence Data; *Protein Folding; Oxidation-Reduction; Interleukin-8/*chemical synthesis/chemistry

Amide bond formation via pentafluorothiophenyl active esters - Davis, Anthony P.; Walsh, John J. (Tetrahedron Lett., 1994)
A number of pentafluorothiophenyl (PFTP) esters were shown to be useful acyl donors for amide bond formation, being non-polar, stable to chromatography and extended storage, but sufficiently active for use with relatively unreactive acyl groups. In particular, the synthesis of amide 4 via PFTP ester 5 proved superior to a range of alternative methods, including the use of the analogous pentafluorophenyl active ester 3.
0040-4039
The following values have no corresponding Zotero field: number: 27

Nucleophilic addition of a water-soluble phosphine to aldehydes. Isolation of (1-hydroxyalkyl)phosphonium salts and the crystal structure of the (1-methoxy-1-benzyl)(m-sulfonatophenyl)diphenylphosphonium salt - Darensbourg, D. J.; Joo, F.; Katho, A.; Stafford, J. N. W.; Benyei, A.; Reibenspies, J. H. (Inorg. Chem., 1994)
null
doi: 10.1021/ic00079a031 0020-1669 doi: 10.1021/ic00079a031
The following values have no corresponding Zotero field: number: 1 publisher: American Chemical Society

Coupling N-Methylated Amino Acids Using PyBroP and PyCloP Halogenophosphonium Salts: Mechanism and Fields of Application - Coste, Jacques; Frerot, Eric; Jouin, Patrick (J. Org. Chem., 1994)
null
doi: 10.1021/jo00088a027 0022-3263 doi: 10.1021/jo00088a027
The following values have no corresponding Zotero field: number: 9 publisher: American Chemical Society

Structure and redox chemistry of analogous nickel thiolato and selenolato complexes: Implications for the nickel sites in hydrogenases - Choudhury, Suranjan B.; Pressler, Michelle A.; Mirza, Shaukat A.; Day, Roberta O.; Maroney, Michael J. (Inorg. Chem., 1994)
doi: 10.1021/ic00100a005 0020-1669 doi: 10.1021/ic00100a005
The following values have no corresponding Zotero field: number: 22 publisher: American Chemical Society

Ab Initio analysis of water-assisted reaction mechanisms in amide hydrolysis - Antonczak, S.; Ruiz-Lopez, M. F.; Rivail, J. L. (J. Am. Chem. Soc., 1994)
doi: 10.1021/ja00088a030 0002-7863 doi: 10.1021/ja00088a030
The following values have no corresponding Zotero field: number: 9 publisher: American Chemical Society

Tributylphosphine: a remarkable acylation catalyst - Vedejs, E.; Diver, S. T. (J. Am. Chem. Soc., 1993)
doi: 10.1021/ja00061a056 0002-7863 doi: 10.1021/ja00061a056
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Tributylphosphine-catalyzed acylations of alcohols: scope and related reactions - Vedejs, E.; Bennett, N. S.; Conn, L. M.; Diver, S. T.; Gingras, M.; Lin, S.; Oliver, P. A.; Peterson, M. J. (J. Org. Chem., 1993)
doi: 10.1021/jo00077a064 0022-3263 doi: 10.1021/jo00077a064
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

Primary structure of a photoactive yellow protein from the phototrophic bacterium Ectothiorhodospira halophila, with evidence for the mass and the binding site of the chromophore - Van Beeumen, J. J.; Devreese, B. V.; Van Bun, S. M.; Hoff, W. D.; Hellingwerf, K. J.; Meyer, T. E.; McRee, D. E.; Cusanovich, M. A. (Protein Sci., 1993)
The complete amino acid sequence of the 125-residue photoactive yellow protein (PYP) from Ectothiorhodospira halophila has been determined to be MEHVAFGSEDIENTLAKMDDGQLDGLAFGAIQLDGDGNILQYNAAEGDITGRDPKEVIGKNFFKDVAP+ ++ CTDSPEFYGKFKEGVASGNLNTMFEYTFDYQMTPTKVKVHMKKALSGDSYWVFVKRV. This is the first sequence to be reported for this class of proteins. There is no obvious sequence homology to any other protein, although the crystal structure, known at 2.4 A resolution (McRee, D.E., et al., 1989, Proc. Natl. Acad. Sci. USA 86, 6533-6537), indicates a relationship to the similarly sized fatty acid binding protein (FABP), a representative of a family of eukaryotic proteins that bind hydrophobic molecules. The amino acid sequence exhibits no greater similarity between PYP and FABP than for proteins chosen at random (8%). The photoactive yellow protein contains an unidentified chromophore that is bleached by light but recovers within a second. Here we demonstrate that the chromophore is bound covalently to Cys 69 instead of Lys 111 as deduced from the crystal structure analysis. The partially exposed side chains of Tyr 76, 94, and 118, plus Trp 119 appear to be arranged in a cluster and probably become more exposed due to a conformational change of the protein resulting from light-induced chromophore bleaching. The charged residues are not uniformly distributed on the protein surface but are arranged in positive and negative clusters on opposite sides of the protein. The exact chemical nature of the chromophore remains undetermined, but we here propose a possible structure based on precise mass analysis of a chromophore-binding peptide by electrospray ionization mass spectrometry and on the fact that the chromophore can be cleaved off the apoprotein upon reduction with a thiol reagent. The molecular mass of the chromophore, including an SH group, is 147.6 Da (+/- 0.5 Da); the cysteine residue to which it is bound is at sequence position 69.
Comparative Study Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. United States a publication of the Protein Society
The following values have no corresponding Zotero field: auth-address: Laboratory of Microbiology, University of Ghent, Belgium. number: 7 accession-num: 8358295
Keywords: Amino Acid Sequence; Models, Molecular; Sequence Homology, Amino Acid; Molecular Sequence Data; Peptide Fragments/chemistry; *Photoreceptors, Microbial; Serine Endopeptidases/metabolism; Spectrophotometry; *Neoplasm Proteins; Amino Acids/analysis; Apoproteins/chemistry; Bacteria/*chemistry; Bacterial Proteins/*chemistry/genetics/metabolism; Carrier Proteins/genetics; Endopeptidase K; Fatty Acid-Binding Proteins; Pigments, Biological/chemistry; Retinol-Binding Proteins/genetics; Sequence Analysis

The eubacterium Ectothiorhodospira halophila is negatively phototactic, with a wavelength dependence that fits the absorption spectrum of the photoactive yellow protein - Sprenger, W. W.; Hoff, W. D.; Armitage, J. P.; Hellingwerf, K. J. (J. Bacteriol., 1993)
The motile, alkalophilic, and extremely halophilic purple sulfur bacterium Ectothiorhodospira halophila is positively photophobotactic. This response results in the accumulation of bacteria in light spots (E. Hustede, M. Liebergesell, and H. G. Schlegel, Photochem. Photobiol. 50:809-815, 1989; D. E. McRee, J. A. Tainer, T. E. Meyer, J. Van Beeumen, M. A. Cusanovich, and E. D. Getzoff, Proc. Natl. Acad. Sci. USA 86:6533-6537, 1989; also, this work). In this study, we demonstrated that E. halophila is also negatively phototactic. Video analysis of free-swimming bacteria and the formation of cell distribution patterns as a result of light-color boundaries in an anaerobic suspension of cells revealed the existence of a repellent response toward intense (but nondamaging) blue light. In the presence of saturating background photosynthetic light, an increase in the intensity of blue light induced directional switches, whereas a decrease in intense blue light gave rise to suppression of these reversals. To our knowledge, this is the first report of a true repellent response to light in a free-swimming eubacterium, since the blue light response in Escherichia coli and Salmonella typhimurium (B. L. Taylor and D. E. Koshland, Jr., J. Bacteriol. 123:557-569, 1975), which requires an extremely high light intensity, is unlikely to be a sensory process. The wavelength dependence of this negative photoresponse was determined with narrow band pass interference filters. It showed similarity to the absorption spectrum of the photoactive yellow protein from E. halophila.
Journal Article Research Support, Non-U.S. Gov't United States
The following values have no corresponding Zotero field: auth-address: Department of Microbiology, University of Amsterdam, The Netherlands. alt-title: Journal of bacteriology number: 10 accession-num: 8491725
Keywords: Spectrum Analysis; Light; *Bacterial Physiological Phenomena; Bacteria/radiation effects; Bacterial Proteins/*metabolism/radiation effects; Biological Assay; Cell Movement/*physiology/radiation effects; Image Processing, Computer-Assisted

A new type of safety-catch linker cleaved by intramolecular activation of an amide anchorage and allowing aqueous processing in solid-phase peptide synthesis - Sola, Regine; Saguer, Philippe; David, Marie-Laure; Pascal, Robert (J. Chem. Soc. Chem. Commun., 1993)
The -phenyloxycarbonyl--2,3-diaminopropionic acid residue behaves as a versatile iinker [Dpr(Phoc)linker] displaying high stability under neutral and acidic conditions but undergoes activation under mild alkaline conditions for the release of peptide acids or amides by nucleophilic cleavage.
The following values have no corresponding Zotero field: number: 23 publisher: The Royal Society of Chemistry work-type: 10.1039/C39930001786

Equilibrium constants for thiol-disulfide interchange reactions: a coherent, corrected set - Lees, Watson J.; Whitesides, George M. (J. Org. Chem., 1993)
null
doi: 10.1021/jo00055a016 0022-3263 doi: 10.1021/jo00055a016
The following values have no corresponding Zotero field: number: 3 publisher: American Chemical Society

Synthetic study on selenocystine-contaning peptides - Koide, Takaki; Itoh, Hiromi; Otaka, Akira; Yasui, Hiroyuki; Kuroda, Masataka; Esaki, Nobuyoshi; Soda, Kenji; Fujii, Nobutaka (Chem. Pharm. Bull., 1993)
The following values have no corresponding Zotero field: number: 3
Keywords: #nosource

Syntheses and biological activities of selenium analogs of alpha-rat atrial natriuretic peptide - Koide, Takaki; Itoh, Hiromi; Otaka, Akira; Furuya, Mayumi; Kitajima, Yasuo; Fujii, Nobutaka (Chem. Pharm. Bull., 1993)
The following values have no corresponding Zotero field: number: 9
Keywords: #nosource

Disulfide structures of highly bridged peptides: a new strategy for analysis - Gray, W. R. (Protein Sci., 1993)
A new approach is described for analyzing disulfide linkage patterns in peptides containing tightly clustered cystines. Such peptides are very difficult to analyze with traditional strategies, which require that the peptide chain be split between close or adjacent Cys residues. The water-soluble tris-(2-carboxyethyl)-phosphine (TCEP) reduced disulfides at pH 3, and partially reduced peptides were purified by high performance liquid chromatography with minimal thiol-disulfide exchange. Alkylation of free thiols, followed by sequencer analysis, provided explicit assignment of disulfides that had been reduced. Thiol-disulfide exchange occurred during alkylation of some peptides, but correct deductions were still possible. Alkylation competed best with exchange when peptide solution was added with rapid mixing to 2.2 M iodoacetamide. Variants were developed in which up to three alkylating agents were used to label different pairs of thiols, allowing a full assignment in one sequencer analysis. Model peptides used included insulin (three bridges, intra- and interchain disulfides; -Cys.Cys- pair), endothelin and apamin (two disulfides; -Cys.x.Cys- pair), conotoxin GI and isomers (two disulfides; -Cys.Cys- pair), and bacterial enterotoxin (three bridges within 13 residues; two -Cys.Cys- pairs). With insulin, all intermediates in the reduction pathway were identified; with conotoxin GI, analysis was carried out successfully for all three disulfide isomers. In addition to these known structures, the method has been applied successfully to the analysis of several previously unsolved structures of similar complexity. Rates of reduction of disulfide bonds varied widely, but most peptides did not show a strongly preferred route for reduction.
NCI 5 P30 CA42014/CA/NCI NIH HHS/United States NSS 2 S07 RR07092/RR/NCRR NIH HHS/United States Journal Article Research Support, U.S. Gov't, P.H.S. United states a publication of the Protein Society
The following values have no corresponding Zotero field: auth-address: Department of Biology, University of Utah, Salt Lake City 84112. number: 10 accession-num: 8251945
Keywords: Amino Acid Sequence; Hydrogen-Ion Concentration; Peptides/*chemistry; Molecular Sequence Data; Chromatography, High Pressure Liquid; Disulfides/*chemistry; Alkylation; Insulin/chemistry; *Conotoxins; Apamin/chemistry; Bacterial Toxins/chemistry; Endothelins/chemistry; Enterotoxins/chemistry; Escherichia coli Proteins; Iodoacetamide; omega-Conotoxin GVIA; Peptides, Cyclic/chemistry

Conformational analysis of carbonyl and thiocarbonyl esters: the HC(=X)YXXXCH(CH3)2 (X,Y = O or S) internal rotation - Teixeira-Dias, J. J. C.; Fausto, R.; de Carvalho, L. A. E. Batista (J. Mol. Struct. THEOCHEM, 1992)
The YXXXCH(CH3)2 internal rotation in the HC(=X)YCH(CH3)2, (X,Y = O or S) series of molecules was studied by the ab initio SCF-MO method using 3–21G and 3–21G + d(0.65S) basis sets. Energies and structures of several conformations of these molecules, determined by gradient geometry refinement, are reported and used to assess the effects of oxygen-bysulphur substitution on molecular properties. The nature and relative importance of intramolecular interactions involving both the −CH(CH3)2 and the HC(=X)Y (X,Y = O or S) fragments are also discussed.
0166-1280

Constructing proteins by dovetailing unprotected synthetic peptides: backbone-engineered HIV protease - Schnolzer, M.; Kent, S. B. H. (Science, 1992)
Backbone-engineered HIV-1 protease was prepared by a total chemical synthesis approach that combines the act of joining two peptides with the generation of an analog structure. Unprotected synthetic peptide segments corresponding to the two halves of the HIV-1 protease monomer polypeptide chain were joined cleanly and in high yield through unique mutually reactive functional groups, one on each segment. Ligation was performed in 6 molar guanidine hydrochloride, thus circumventing limited solubility of protected peptide segments, the principal problem of the classical approach to the chemical synthesis of proteins. The resulting fully active HIV-1 protease analog contained a thioester replacement for the natural peptide bond between Gly51-Gly52 in each of the two active site flaps, a region known to be highly sensitive to mutational changes of amino acid side chains.
Schnolzer, M Kent, S B New York, N.Y. Science. 1992 Apr 10;256(5054):221-5.
The following values have no corresponding Zotero field: auth-address: Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037. number: 5054 edition: 1992/04/10 accession-num: 1566069 work-type: Research Support, Non-U.S. Gov't
Keywords: Amino Acid Sequence; Models, Molecular; Protein Conformation; Molecular Sequence Data; Mass Spectrometry; HIV-1/*enzymology; Peptides/*chemical synthesis; Indicators and Reagents; Guanidine; Guanidines; HIV Protease/*chemical synthesis/metabolism

In situ neutralization in Boc-chemistry solid phase peptide synthesis. Rapid, high yield assembly of difficult sequences - Schnolzer, M.; Alewood, P.; Jones, A.; Alewood, D.; Kent, S. B. H. (Int. J. Pept. Protein Res., 1992)
The following values have no corresponding Zotero field: auth-address: Scripps Research Institute, La Jolla, CA. number: 3-4 edition: 1992/09/01 accession-num: 1478777
Keywords: Stereoisomerism; Acetylation; Chromatography, High Pressure Liquid; Mass Spectrometry; Glutamine/chemistry; Time Factors; HIV Protease/chemical synthesis; Peptides/*chemical synthesis; Peptide Fragments/chemical synthesis; *Polystyrenes; *Resins, Synthetic; Acyl Carrier Protein/chemical synthesis; Formic Acid Esters/*chemistry

Pega: a flow stable polyethylene glycol dimethyl acrylamide copolymer for solid phase synthesis - Meldal, Morten (Tetrahedron Lett., 1992)
0040-4039 doi: 10.1016/S0040-4039(00)79604-3
The following values have no corresponding Zotero field: number: 21

Resolution of proline acylation problem for thiol capture strategy by use of a chloro-dibenzofuran template - Fotouhi, N.; Bowen, B. R.; Kemp, D. S. (Int. J. Pept. Protein Res., 1992)
The acyl transfer rate for proline, in the prior thiol capture strategy, was enhanced by changing the electronic character of the dibenzofuran template. The rate of amide bond formation between proline and cysteine by the 1-chloro-4-hydroxy-6-mercaptodibenzofuran was measured to be 0.012 min-1, which translates to a half-life of 53 min. Further enhancement of the reaction rate was accomplished by the use of a 1,3-dichloro-dibenzofuran template. The k1 for the reaction was measured to be 0.093 min-1, and the half-life was calculated to be 7 min. To test the applicability of the activated template, 1-chloro-4-hydroxy-6-mercaptodibenzofuran, in peptide synthesis, the 34 amino acid long peptide, H-RPDFCLEPPYTGPCRKARNNFKSADECMRTCGGA-OH, was synthesized. This peptide represents the condensation of the N-terminal 13-mer and the C-terminal 21-mer of the basic pancreatic trypsin inhibitor.
Fotouhi, N Bowen, B R Kemp, D S GM 13453/GM/NIGMS NIH HHS/ Denmark Int J Pept Protein Res. 1992 Aug;40(2):141-7.
The following values have no corresponding Zotero field: auth-address: Massachusetts Institute of Technology, Cambridge. alt-title: International journal of peptide and protein research number: 2 edition: 1992/08/01 accession-num: 1280251 work-type: Research Support, U.S. Gov't, P.H.S.
Keywords: Amino Acid Sequence; Kinetics; Cysteine/chemistry; Molecular Sequence Data; Acetylation; Proline/*chemistry; Peptides/*chemical synthesis; Sulfhydryl Compounds/chemical synthesis/*chemistry; Aprotinin/chemical synthesis; Benzofurans/*chemistry

Chemical heterogeneity as a result of hydroxylamine cleavage of a fusion protein of human insulin-like growth factor I - Canova-Davis, E.; Eng, M.; Mukku, V.; Reifsnyder, D. H.; Olson, C. V.; Ling, V. T. (Biochem. J., 1992)
Recombinant DNA techniques were used to biosynthesize human insulin-like growth factor I (hIGF-I) as a fusion protein wherein the fusion polypeptide is an IgG-binding moiety derived from staphylococcal protein A. This fusion protein is produced in Escherichia coli and secreted into the fermentation broth. In order to release mature recombinant-derived hIGF-I (rhIGF-I), the fusion protein is treated with hydroxylamine, which cleaves a susceptible Asn-Gly bond that has been engineered into the fusion protein gene. Reversed-phase h.p.l.c. was used to estimate the purity of the rhIGF-I preparations, especially for the quantification of the methionine sulphoxide-containing variant. It was determined that hydroxylamine cleavage of the fusion protein produced, as a side reaction, hydroxamates of the asparagine and glutamine residues in rhIGF-I. Although isoelectric focusing was effective in detecting, and reversed-phase h.p.l.c. for producing enriched fractions of the hydroxamate variants, ion-exchange chromatography was a more definitive procedure, as it allowed quantification and facile removal of these variants. The identity of the variants as hydroxamates was established by Staphylococcus aureus V8 proteinase digestion, followed by m.s., as the modification was transparent to amino acid and N-terminal sequence analyses. The biological activity of rhIGF-I was established by its ability to incorporate [3H]thymidine into the DNA of BALB/c373 cells and by a radioreceptor assay utilizing human placental membranes. Both assays demonstrate that the native, recombinant and methionine sulphoxide and hydroxamate IGF-I variants are essentially equipotent.
Journal Article England
The following values have no corresponding Zotero field: auth-address: Department of Medicinal and Analytical Chemistry, Genentech Inc., South San Francisco, CA 94080. alt-title: The Biochemical journal accession-num: 1637301
Keywords: Amino Acid Sequence; Animals; Humans; Molecular Sequence Data; Chromatography, High Pressure Liquid; Mice; Escherichia coli; Mice, Inbred BALB C; Recombinant Fusion Proteins/chemistry/genetics/*metabolism; 3T3 Cells; Chromatography, Ion Exchange; Hydroxylamine; Hydroxylamines/*metabolism; Insulin-Like Growth Factor I/chemistry/genetics/*metabolism; Isoelectric Focusing; Radioligand Assay; Serine Endopeptidases; Staphylococcal Protein A/chemistry/genetics/metabolism

Purification of synthetic peptides using reversible chromatographic probes based on the Fmoc molecule - Ball, H. L.; Mascagni, P. (Int. J. Pept. Protein Res., 1992)
A rapid, versatile, reversible procedure for purifying synthetic peptides has been developed based on the specific incorporation of 4-carboxylate Fmoc derivatives onto the terminal amino acid of peptidyl-resins. The acid stable 4-COR-Fmoc derivatives were synthesised with a variety of chemical groups thus altering the chromatographic properties of the "target" peptides and permitting their convenient purification, either by reversed-phase HPLC or ion exchange chromatography. The assembly of the peptides involved a capping step to prevent the formation of deletion forms. The 4-COR-Fmoc derivatives were incorporated either as preformed amino acid conjugates or as activated succinimidyl esters. After HF cleavage and purification the 4-COR-Fmoc probes were quantitatively removed with organic bases. The efficiency of the technique was demonstrated by the purification of small to large sized peptides, including a cyclic analogue.
0367-8377 (Print) 0367-8377 (Linking) Journal Article Research Support, Non-U.S. Gov't
The following values have no corresponding Zotero field: auth-address: Italfarmaco Research Centre, Milan, Italy. number: 5 accession-num: 1483831
Keywords: Amino Acid Sequence; Molecular Sequence Data; Fluorenes/*chemistry; Chromatography, High Pressure Liquid/*methods; Peptide Fragments/chemistry; Peptides/chemical synthesis/*isolation & purification; *Molecular Probes; Amino Acids/analysis/*chemistry; HIV Core Protein p24/chemistry; Spectrometry, Mass, Fast Atom Bombardment

Evidence for the identity of human scatter factor and human hepatocyte growth factor - Weidner, K. M.; Arakaki, N.; Hartmann, G.; Vandekerckhove, J.; Weingart, S.; Rieder, H.; Fonatsch, C.; Tsubouchi, H.; Hishida, T.; Daikuhara, Y.; et al (Proc. Natl. Acad. Sci. U. S. A., 1991)
Scatter factor (SF), a secretory protein of fibroblasts, dissociates and increases the motility of epithelial cells and may be involved in cell migration processes during embryogenesis and tumor progression. Hepatocyte growth factor (HGF), a protein isolated from serum of patients with liver failure, is a potent mitogen for hepatocytes and is thought to play a role in liver regeneration. Here we present structural and functional evidence that human SF and human HGF (and also the human lung fibroblast-derived mitogen) are identical proteins encoded by a single gene, since (i) no major difference could be found by protein sequencing, by cDNA analysis, and by immunological comparison and (ii) SF in fact acts as a hepatocyte growth factor--i.e., stimulates DNA synthesis of activity--i.e., dissociates and induces invasiveness of various epithelial cells. The human SF/HGF gene was localized to chromosome bands 7q11.2-21. These results have important consequences for further studies on the involvement of SF/HGF as a modulator of cellular growth and motility in embryonal, malignant, and regenerative processes.
0027-8424 (Print) 0027-8424 (Linking) Comparative Study Journal Article Research Support, Non-U.S. Gov't
The following values have no corresponding Zotero field: auth-address: Institut fur Zellbiologie (Tumorforschung), Medical School, Essen, Federal Republic of Germany. number: 16 accession-num: 1831266
Keywords: Amino Acid Sequence; Animals; Humans; Cell Line; Molecular Sequence Data; Base Sequence; Cloning, Molecular; Cell Division/drug effects; *Chromosomes, Human, Pair 7; Chromosome Banding; Chromosome Mapping; Cytokines/*genetics/isolation & purification/pharmacology; DNA Replication/drug effects; Fibroblasts/physiology; Hepatocyte Growth Factor; Interleukin-6/*genetics/isolation & purification/pharmacology; Oligonucleotide Probes; Recombinant Proteins/isolation & purification/pharmacology; Transfection

The atom economy-a search for synthetic efficiency - Trost, B. M. (Science, 1991)
Efficient synthetic methods required to assemble complex molecular arrays include reactions that are both selective (chemo-, regio-, diastereo-, and enantio-) and economical in atom count (maximum number of atoms of reactants appearing in the products). Methods that involve simply combining two or more building blocks with any other reactant needed only catalytically constitute the highest degree of atom economy. Transition metal-catalyzed methods that are both selective and economical for formation of cyclic structures, of great interest for biological purposes, represent an important starting point for this long-term goal. The limited availability of raw materials, combined with environmental concerns, require the highlighting of these goals.
The following values have no corresponding Zotero field: number: 5037 work-type: 10.1126/science.1962206

A new convenient approach to peptide synthesis using a diselenide and a phosphine - Singh, Usha; Ghosh, Sunil K.; Chadha, Mohindra S.; Mamdapur, Vasant R. (Tetrahedron Lett., 1991)
The following values have no corresponding Zotero field: number: 2

Scatter factor and hepatocyte growth factor are indistinguishable ligands for the MET receptor - Naldini, L.; Weidner, K. M.; Vigna, E.; Gaudino, G.; Bardelli, A.; Ponzetto, C.; Narsimhan, R. P.; Hartmann, G.; Zarnegar, R.; Michalopoulos, G. K.; et al (EMBO J., 1991)
Scatter Factor (SF) is a fibroblast-secreted protein which promotes motility and matrix invasion of epithelial cells. Hepatocyte Growth Factor (HGF) is a powerful mitogen for hepatocytes and other epithelial tissues. SF and HGF, purified according to their respective biological activities, were interchangeable and equally effective in assays for cell growth, motility and invasion. Both bound with identical affinities to the same sites in target cells. The receptor for SF and HGF was identified as the product of the MET oncogene by: (i) ligand binding and coprecipitation in immunocomplexes; (ii) chemical crosslinking to the Met beta subunit; (iii) transfer of binding activity in insect cells by a baculovirus carrying the MET cDNA; (iv) ligand-induced tyrosine phosphorylation of the Met beta subunit. SF and HGF cDNA clones from human fibroblasts, placenta and liver had virtually identical sequences. We conclude that the same molecule (SF/HGF) acts as a growth or motility factor through a single receptor in different target cells.
0261-4189 (Print) 0261-4189 (Linking) Journal Article Research Support, Non-U.S. Gov't
The following values have no corresponding Zotero field: auth-address: Department of Biomedical Sciences and Oncology, University of Torino, School Medicine, Italy. number: 10 accession-num: 1655405
Keywords: Animals; Phosphorylation; Ligands; Cells, Cultured; Rats; Cloning, Molecular; Electrophoresis, Polyacrylamide Gel; Proto-Oncogene Proteins c-met; Radioligand Assay; Hepatocyte Growth Factor; Autoradiography; Baculoviridae/genetics; Blotting, Western; Cross-Linking Reagents; Cytokines/*metabolism; DNA/genetics; Fibroblasts/metabolism; Growth Substances/*metabolism; Proto-Oncogene Proteins/genetics/*metabolism; Receptors, Cell Surface/genetics/*metabolism

Polypeptide synthesis using the S-Alkyl thioester of a partially protected peptide segment. Synthesis of the DNA-binding domain of c-Myb protein (142–193)–NH2 - Hojo, H.; Aimoto, S. (Bull. Chem. Soc. Jpn., 1991)
The following values have no corresponding Zotero field: number: 1
Keywords: #nosource

HBTU activation for automated Fmoc solid-phase peptide synthesis - Fields, C. G.; Lloyd, D. H.; Macdonald, R. L.; Otteson, K. M.; Noble, R. L. (Pept. Res., 1991)
Excellent results have been obtained for the Fmoc solid-phase syntheses of peptides using the activating reagent 2-(1H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluronium hexafluorophosphate (HBTU). Activation occurs very rapidly in N,N-dimethylformamide and N-methyl-pyrrolidone, optimal solvents for peptide-resin solvation. It has been observed that complete coupling reactions occur in only 10-30 min. Residues such as Arg, Ile, Leu and Val, which often require double coupling by other activation methods, react with high efficiency by single coupling when HBTU is used. The Fmoc/HBTU chemistry has recently been applied to the peptide synthesizers. The incorporation of trityl side-chain protection for Fmoc-Asn and Fmoc-Gln further enhances coupling efficiencies in difficult sequences.
1040-5704 (Print) 1040-5704 (Linking) Journal Article
The following values have no corresponding Zotero field: auth-address: Applied Biosystems Inc., Foster City, CA 94404. number: 2 accession-num: 1815783
Keywords: Amino Acid Sequence; Kinetics; Molecular Sequence Data; Peptides/*chemical synthesis; Automation; Amino Acids/analysis; *Fluorenes; *Triazoles; Piperidines/analysis; Urea/*analogs & derivatives

Hydrogen bond directed cocrystallization and molecular recognition properties of acyclic imides - Etter, Margaret C.; Reutzel, Susan M. (J. Am. Chem. Soc., 2013)
doi: 10.1021/ja00007a037
The following values have no corresponding Zotero field: number: 7 publisher: American Chemical Society

tert-Butyloxycarbonyl and benzyloxycarbonyl amino acid fluorides. New, stable rapid-acting acylating agents for peptide synthesis - Carpino, Louis A.; Mansour, El-Sayed M. E.; Sadat-Aalaee, Dean (J. Org. Chem., 1991)
null
doi: 10.1021/jo00008a005 0022-3263 doi: 10.1021/jo00008a005
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Selective reduction of disulfides by tris(2-carboxyethyl)phosphine - Burns, John A.; Butler, James C.; Moran, John; Whitesides, George M. (J. Org. Chem., 2014)
doi: 10.1021/jo00008a014
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Arg-Gly-Asp constrained within cyclic pentapeptides. Strong and selective inhibitors of cell adhesion to vitronectin and laminin fragment P1 - Aumailley, M.; Gurrath, M.; Muller, G.; Calvete, J.; Timpl, R.; Kessler, H. (FEBS Lett, 1991)
Cyclic Arg-Gly-Asp-Phe-Val peptides with either D-Phe or D-Val residues were 20- to more than 100-fold better inhibitors of cell adhesion to vitronectin and/or laminin fragment P1 when compared to a linear variant or Gly-Arg-Gly-Asp-Ser. No or only little increase in inhibitory capacity was observed for fibronectin adhesion and for the binding of platelet receptor alpha IIb beta 3 to fibrinogen. NMR studies of the two most active cyclic peptides showed for both an all-trans conformation with a beta II' and gamma turn. Subtle conformational differences, however, exist between both peptides and may contribute to selectivity of inhibition.
Aumailley, M Gurrath, M Muller, G Calvete, J Timpl, R Kessler, H Research Support, Non-U.S. Gov't Netherlands FEBS letters FEBS Lett. 1991 Oct 7;291(1):50-4.
The following values have no corresponding Zotero field: auth-address: Max-Planck-Institut fur Biochemie, Martinsried, Germany. number: 1 edition: 1991/10/07 accession-num: 1718779
Keywords: Amino Acid Sequence; Animals; Humans; Protein Conformation; Molecular Sequence Data; Oligopeptides/*chemistry; Mice; Structure-Activity Relationship; Peptides, Cyclic/*chemistry; *Cell Adhesion; Glycoproteins/*metabolism; Integrins/metabolism; Laminin/*metabolism; Vitronectin

Degenerate intermolecular thiolate-disulfide interchange involving cyclic five-membered disulfides is faster by .apprx.103 than that involving six- or seven-membered disulfides - Singh, Rajeeva; Whitesides, George M. (J. Am. Chem. Soc., 1990)
null
doi: 10.1021/ja00173a018 0002-7863 doi: 10.1021/ja00173a018
The following values have no corresponding Zotero field: number: 17 publisher: American Chemical Society

A safety-catch type of amide protecting group - Patek, Marcel; Lebl, Michal (Tetrahedron Lett., 1990)
A p-substituted benzhydrylamine derivatives 1 – 4 were synthesized and evaluated for their lability toward various acids. The pair 2 & 4 seems to be suitable for peptide synthesis using the base labile Fmoc- and/or acid labile Boc- strategy
The following values have no corresponding Zotero field: number: 36

Thio-alpha-amino acids (S-acids) as a carboxyl component in peptide synthesis catalysed by papain - Mitin Yu, V.; Zapevalova, N. P. (Int. J. Pept. Protein Res., 1990)
Peptide synthesis catalysed by papain was studied using thio-alpha-amino acids (S-acids) as a carboxyl component. It was found, for example, that with Z-AlaSH (pK 2.70) the maximal yield of the peptide Z-AlaValNH2 was obtained at pH 8-8.5. A two-fold excess of Z-AlaSH furnished peptides with yields close to 100%. Thio-amino acids with bulky side groups, for example, Z-IleSH, Z-Asp(OBu')SH, gave peptides with a low yield. Papain interacts with Z-AlaSH better than do bromelain or ficin.
Mitin YuV Zapevalova, N P Denmark International journal of peptide and protein research Int J Pept Protein Res. 1990 Apr;35(4):352-6.
The following values have no corresponding Zotero field: auth-address: Laboratory of Peptide Chemistry, Academy of Sciences of the USSR, Pushchino, Moscow Region. number: 4 edition: 1990/04/01 accession-num: 2345057
Keywords: Amino Acid Sequence; Catalysis; Molecular Sequence Data; Peptides/*chemical synthesis; *Amino Acids/analysis; *Papain; *Sulfur

A cleavage method which minimizes side reactions following Fmoc solid phase peptide synthesis - King, D. S.; Fields, C. G.; Fields, G. B. (Int. J. Pept. Protein Res., 1990)
The success of solid phase peptide synthesis utilizing 9-fluorenylmethoxycarbonyl (Fmoc) amino acids is often limited by deleterious side reactions which occur during TFA peptide-resin cleavage and side-chain deprotection. The majority of these side reactions modify susceptible residues, such as Trp, Tyr, Met, and Cys, with TFA-liberated side-chain protecting groups and linkers. The purpose of this study was to assess the relative effectiveness of various scavengers in suppressing these side reactions. We found that the cleavage mixture 82.5% TFA : 5% phenol : 5% H2O : 5% thioanisole : 2.5% EDT (Reagent K) was maximally efficient in inhibiting a great variety of side reactions. Synthesis and cleavage of 10 peptides, each containing 20-50 residues, demonstrated the complementarity of Fmoc chemistry with Reagent K for efficient synthesis of complex peptides.
Journal Article Denmark
The following values have no corresponding Zotero field: auth-address: Department of Molecular and Cell Biology, University of California, Berkeley. alt-title: International journal of peptide and protein research number: 3 accession-num: 2279849
Keywords: Amino Acid Sequence; Molecular Sequence Data; Chromatography, High Pressure Liquid; Methods; Trifluoroacetic Acid; *Fluorenes; *Amino Acids; Mercaptoethanol/analogs & derivatives; Peptides/*chemical synthesis/isolation & purification

Quantitative modeling of proximity effects on organic reactivity - Houk, Kendall N.; Tucker, John A.; Dorigo, Andrea E. (Acc. Chem. Res., 1990)
doi: 10.1021/ar00172a003 0001-4842 doi: 10.1021/ar00172a003
The following values have no corresponding Zotero field: number: 4 publisher: American Chemical Society

Solid phase peptide synthesis utilizing 9-fluorenylmethoxycarbonyl amino acids - Fields, G. B.; Noble, R. L. (Int. J. Pept. Protein Res., 1990)
9-Fluorenylmethoxycarbonyl (Fmoc) amino acids were first used for solid phase peptide synthesis a little more than a decade ago. Since that time, Fmoc solid phase peptide synthesis methodology has been greatly enhanced by the introduction of a variety of solid supports, linkages, and side chain protecting groups, as well as by increased understanding of solvation conditions. These advances have led to many impressive syntheses, such as those of biologically active and isotopically labeled peptides and small proteins. The great variety of conditions under which Fmoc solid phase peptide synthesis may be carried out represents a truly "orthogonal" scheme, and thus offers many unique opportunities for bioorganic chemistry.
0367-8377 (Print) 0367-8377 (Linking) Comparative Study Journal Article Review
The following values have no corresponding Zotero field: auth-address: Department of Pharmaceutical Chemistry, University of California, San Francisco. number: 3 accession-num: 2191922
Keywords: Molecular Structure; Peptides/*chemical synthesis; Solvents; Resins, Plant; *Fluorenes; *Amino Acids; Chemical Phenomena; Chemistry; Chemistry, Physical; Microscopy, Electron; Physicochemical Phenomena

Succinimide formation from aspartyl and asparaginyl peptides as a model for the spontaneous degradation of proteins - Stephenson, R. C.; Clarke, S. (J. Biol. Chem., 1989)
Nonenzymatic intramolecular reactions can result in the deamidation, isomerization, and racemization of protein and peptide asparaginyl and aspartyl residues via succinimide intermediates. To understand the sequence dependence of these reactions, we measured the rate of succinimide formation in a series of synthetic peptides at pH 7.4. These peptides (Val-Tyr-Pro-X-Y-Ala) contained an internal aspartyl, asparaginyl, aspartyl beta-methyl ester, or aspartyl alpha-methyl ester residue (X) followed by a glycyl, seryl, or alanyl residue (Y). The rates of succinimide formation of the asparaginyl peptides were found to be 13.1-35.6 times faster than those of the aspartyl peptides. The rates of succinimide formation for the glycyl peptides were 6.5-17.6 times faster than those of the alanyl peptides, while the rates for the seryl peptides were 1.6-4.5 times faster than those of the alanyl peptides. The overall 232-fold range in these reaction rates for aspartyl and asparaginyl residues suggests that sequence can be an important determinant in their stability in flexible peptides. In proteins, there may be a much larger range in the rates of succinimide formation because specific conformations may greatly enhance or inhibit this reaction.
Stephenson, R C Clarke, S GM 07185/GM/NIGMS NIH HHS/United States Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. United States J Biol Chem. 1989 Apr 15;264(11):6164-70.
The following values have no corresponding Zotero field: auth-address: Department of Chemistry and Biochemistry, University of California, Los Angeles 90024. alt-title: The Journal of biological chemistry number: 11 edition: 1989/04/15 accession-num: 2703484 remote-database-provider: NLM
Keywords: Amino Acid Sequence; Kinetics; Esters; Structure-Activity Relationship; Oligopeptides; Chemical Phenomena; Chemistry; Asparagine; Aspartic Acid; In Vitro Techniques; Proteins; Succinimides; #nosource

Solubilization of peptides in non-polar organic solvents by the addition of inorganic salts: Facts and implications - Seebach, Dieter; Thaler, Adrian; Beck, Albert K. (Helv. Chim. Acta, 1989)
1522-2675
The following values have no corresponding Zotero field: number: 5 publisher: WILEY-VCH Verlag GmbH

Kinetics of disulfide exchange reactions of monomer and dimer loops of cysteine-valine-cysteine peptides - Zhang, R.; Snyder, G. H. (Biochem., 1988)
Rate constants have been determined in 3 M guanidine hydrochloride for disulfide exchange reactions between glutathione and two synthetic peptides containing a cysteine-valine-cysteine region. Equilibrium experiments demonstrate the absence of noncovalent peptide aggregation in this solvent. Procedures are given for separating seven different components in quenched reactions, including the fully reduced cysteine cluster, the monomeric disulfide loop, parallel and antiparallel dimer loops, and the three monomers containing one or two mixed disulfides with glutathione. Intramolecular rate constants for (1) formation of a sterically strained monomer loop, (2) transfer of glutathione between the two cysteines on the same peptide chain, and (3) formation of unstrained dimer loops correspond to a series of processes forming rings of increasing size. In one sequence, these rate constants are 3, 6, and about 21 s-1, respectively. The larger loops are formed more easily. In the other sequence, rate constants for formation and opening of monomer loops are accelerated 180- and 1300-fold, respectively, relative to analogous reactions in a peptide containing eight residues between the two cysteines. This gives a 7-fold smaller equilibrium constant for ring closure in the cysteine cluster. Dimer formation occurs by a mechanism utilizing the accelerated opening of monomer loops. Results provide information assisting efforts to develop strategies for directing disulfide pairing in novel protein structures. Results also help define factors contributing to formation of undesired oligomers during efforts to refold cysteine-containing proteins obtained by bacterial expression of mammalian genes.
The following values have no corresponding Zotero field: auth-address: Department of Biological Sciences, State University of New York, Buffalo 14260. alt-title: Biochemistry number: 10 edition: 1988/05/17 accession-num: 3408727 work-type: Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.
Zhang, R Snyder, G H GM 26715/GM/NIGMS NIH HHS/ Biochemistry. 1988 May 17;27(10):3785-94.
Keywords: Protein Conformation; Kinetics; Chromatography, High Pressure Liquid; Oxidation-Reduction; Indicators and Reagents; Cysteine; Disulfides; *Oligopeptides/chemical synthesis; Glutathione; Valine

New strategy for the chemical synthesis of proteins - Yajima, Haruaki; Fujii, Nobutaka; Funakoshi, Susumu; Watanabe, Toshihiro; Murayama, Eigoro; Otaka, Akira (Tetrahedron, 1988)
For the chemical synthesis of proteins, an efficient deprotecting procedure by combination of a hard acid, trimethylsilyl trifluoromethanesulfonate, and a soft nucleophile, such as thioanisole, is described. For disulfide bond formation, two new procedures are presented; the one by oxidation with thallium(III) trifluoroacetate and the other by the acid-catalyzed reaction, involving S-substituted cysteine sulfoxides.
0040-4020
The following values have no corresponding Zotero field: number: 3

Chemical synthesis of peptides and proteins - Kent, S. B. H. (Annu. Rev. Biochem., 1988)
Kent, S B Annu Rev Biochem. 1988;57:957-89.
The following values have no corresponding Zotero field: auth-address: Division of Biology, California Institute of Technology, Pasadena 91125. alt-title: Annual review of biochemistry edition: 1988/01/01 accession-num: 3052294 work-type: Review
Keywords: Proteins/*chemical synthesis; Peptides/*chemical synthesis

Structure of ubiquitin refined at 1.8 A resolution - Vijay-Kumar, S.; Bugg, C. E.; Cook, W. J. (J. Mol. Biol., 1987)
The crystal structure of human erythrocytic ubiquitin has been refined at 1.8 A resolution using a restrained least-squares procedure. The crystallographic R-factor for the final model is 0.176. Bond lengths and bond angles in the molecule have root-mean-square deviations from ideal values of 0.016 A and 1.5 degrees, respectively. A total of 58 water molecules per molecule of ubiquitin are included in the final model. The last four residues in the molecule appear to have partial occupancy or large thermal motion. The overall structure of ubiquitin is extremely compact and tightly hydrogen-bonded; approximately 87% of the polypeptide chain is involved in hydrogen-bonded secondary structure. Prominent secondary structural features include three and one-half turns of alpha-helix, a short piece of 3(10)-helix, a mixed beta-sheet that contains five strands, and seven reverse turns. There is a marked hydrophobic core formed between the beta-sheet and alpha-helix. The molecule features a number of unusual secondary structural features, including a parallel G1 beta-bulge, two reverse Asx turns, and a symmetrical hydrogen-bonding region that involves the two helices and two of the reverse turns.
CA-13148/CA/NCI NIH HHS/United States DE-02670/DE/NIDCR NIH HHS/United States GM-27144/GM/NIGMS NIH HHS/United States etc. Journal Article Research Support, U.S. Gov't, P.H.S. England
The following values have no corresponding Zotero field: alt-title: Journal of molecular biology number: 3 accession-num: 3041007
Keywords: Amino Acid Sequence; Humans; Protein Conformation; Molecular Conformation; Hydrogen Bonding; *Ubiquitins; Crystallography; Water

Scatter factor is a fibroblast-derived modulator of epithelial cell mobility - Stoker, M.; Gherardi, E.; Perryman, M.; Gray, J. (Nature, 1987)
Various factors are known to regulate cell growth and differentiation, but less is known of agents which affect movement and positioning, particularly in epithelial-mesenchymal interactions. Cultured human embryo fibroblasts release a protein with a relative molecular mass (Mr) of approximately 50,000 (50K) that affects epithelial cells by causing a disruption of junctions, an increase in local motility and a scattering of contiguous sheets of cells. To investigate specificity, a range of cells has been examined for the ability to produce the factor and for sensitivity to its action. Most freshly isolated normal epithelia and epithelia from cell lines of normal tissue, but not epithelia from tumour cell lines or fibroblasts, were sensitive to scatter factor. In contrast, production of the factor, as identified by activity and by chromatography, was restricted to embryonic fibroblasts and certain variants of 3T3 and BHK21 cells and their transformed derivatives. We conclude that the scatter factor is a paracrine effector of epithelial-mesenchymal interaction, which affects the intercellular connections and mobility of normal epithelial cells. The factor might be involved in epithelial migration, such as occurs in embryogenesis or wound healing.
0028-0836 (Print) 0028-0836 (Linking) Journal Article
The following values have no corresponding Zotero field: number: 6119 accession-num: 2952888
Keywords: Animals; Humans; Cell Line; Protein Biosynthesis; Molecular Weight; *Cell Movement; Hepatocyte Growth Factor; Cell Communication; Embryo, Mammalian; Epithelial Cells; Fibroblasts/*metabolism; Mesoderm/cytology; Neoplasms/pathology; Proteins/*pharmacology

A method for removal of trace iron contamination from biological buffers - Gutteridge, J. M. (FEBS Lett., 1987)
Laboratory chemicals and reagents normally contain trace amounts of iron salts sufficient to catalyse free radical reactions. This iron contamination can be removed from buffers and reagents using a dialysis sac containing a high-affinity iron-binding protein like conalbumin or transferrin without altering the pH value of the fluid.
Gutteridge, J M England FEBS Lett. 1987 Apr 20;214(2):362-4.
The following values have no corresponding Zotero field: alt-title: FEBS letters number: 2 edition: 1987/04/20 accession-num: 2436948
Keywords: Bleomycin; Buffers/*isolation & purification; Conalbumin; Dialysis; Indicators and Reagents/isolation & purification; Iron/*isolation & purification; Transferrin

Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation - Geiger, T.; Clarke, S. (J. Biol. Chem., 1987)
Aspartyl and asparaginyl deamidation, isomerization, and racemization reactions have been studied in synthetic peptides to model these spontaneous processes that alter protein structure and function. We show here that the peptide L-Val-L-Tyr-L-Pro-L-Asn-Gly-L-Ala undergoes a rapid deamidation reaction with a half-life of only 1.4 days at 37 degrees C, pH 7.4, to give an aspartyl succinimide product. Under these conditions, the succinimide product can further react by hydrolysis (half-time, 2.3h) and by racemization (half-time, 19.5 h). The net product of the deamidation reaction is a mixture of L- and D-normal aspartyl and beta-transpeptidation (isoaspartyl) hexapeptides. Replacement of the asparagine residue by an aspartic acid residue results in a 34-fold decrease in the rate of succinimide formation. Significant racemization was found to accompany the deamidation and isomerization reactions, and most of this could be accounted for by the rapid racemization of the succinimide intermediate. Replacement of the glycyl residue in the asparagine-containing peptide with a bulky leucyl or prolyl residue results in a 33-50-fold decrease in the rate of degradation. Peptide cleavage products are observed when these Asn-Leu and Asn-Pro-containing peptides are incubated. Our studies indicate that both aspartic acid and asparagine residues may be hot spots for the nonenzymatic degradation of proteins, especially in cells such as erythrocytes and eye lens, where these macromolecules must function for periods of about 120 days and 80 years, respectively.
Geiger, T Clarke, S EY 04912/EY/NEI NIH HHS/ GM 26020/GM/NIGMS NIH HHS/ J Biol Chem. 1987 Jan 15;262(2):785-94.
The following values have no corresponding Zotero field: alt-title: The Journal of biological chemistry number: 2 edition: 1987/01/15 accession-num: 3805008 work-type: Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S.
Keywords: Amino Acid Sequence; Kinetics; Chromatography, High Pressure Liquid; *Aspartic Acid; Isomerism; Chemical Phenomena; Chemistry; Succinimides; *Asparagine; *Oligopeptides/isolation & purification; *Proteins

2,2,2-Triphenyl-4,5-(2',2"-biphenylene)-1,3,2-dioxaphospholane: an effective reagent for converting diols, amino alcohols, and especially mercapto alcohols to the corresponding heterocycles - Kelly, Jeffery W.; Robinson, Philip L.; Evans, Slayton A. (J. Org. Chem., 1986)
doi: 10.1021/jo00373a026 0022-3263 doi: 10.1021/jo00373a026
The following values have no corresponding Zotero field: number: 23 publisher: American Chemical Society

Human hepatocyte growth factor in plasma from patients with fulminant hepatic failure - Gohda, E.; Tsubouchi, H.; Nakayama, H.; Hirono, S.; Takahashi, K.; Koura, M.; Hashimoto, S.; Daikuhara, Y. (Exp. Cell. Res., 1986)
Plasma from patients with fulminant hepatic failure obtained during plasma exchange therapy, like their serum, demonstrated marked stimulatory activity on DNA synthesis in cultured rat hepatocytes. Heat treatment at 56 degrees C for 30 min did not affect this activity of the plasma, but reduced that of the serum. This growth-promoting activity was confirmed by showing that the patients' serum and plasma increased the labeling index with [3H]thymidine and the total number of nuclei in hepatocyte cultures. The activity of pooled active fractions obtained by gel filtration of the heated plasma was lost completely on heat treatment at 80 degrees C for 10 min or on treatment with trypsin or chymotrypsin, which suggests that it was due to a protein. The human hepatocyte growth factor was purified about 600-fold from heated plasma of a patient by ammonium sulfate precipitation and chromatographies on Affi-Gel Blue and hydroxylapatite. The maximum effect of this partially purified factor on DNA synthesis in cultured hepatocytes was greater than that of epidermal growth factor. The molecular weight of the hepatocyte growth factor was about 85,000 as determined by SDS-PAGE.
0014-4827 (Print) 0014-4827 (Linking) Journal Article Research Support, Non-U.S. Gov't
The following values have no corresponding Zotero field: number: 1 accession-num: 3527727
Keywords: Animals; Humans; Cells, Cultured; Rats; Molecular Weight; DNA/biosynthesis; Epidermal Growth Factor/pharmacology; Growth Substances/*blood/isolation & purification/pharmacology; Hot Temperature; Insulin/pharmacology; Liver Diseases/*blood; Liver/*cytology/metabolism

Chemical synthesis of alpha-inhibin-92 by the thiocarboxyl segment coupling method - Blake, J.; Yamashiro, D.; Ramasharma, K.; Li, C. H. (Int. J. Pept. Protein Res., 1986)
The amino acid residue peptide, alpha-inhibin-92 (alpha-IB-92), has been synthesized by the thiocarboxyl segment strategy. Three segments were synthesized by the solid phase method, purified, and characterized: [GlyS34]-alpha-IB-92-(1-34) (I), CF3CO-[GlyS65]-alpha-IB-92-(35-65) (II), and Msc-alpha-IB-92-(66-92) (III). All were reacted with citraconic anhydride followed by removal of the Msc group in III to give Ia, IIa, and IIIa, respectively. Peptide IIIa was coupled to IIa by the silver nitrate/N-hydroxysuccinimide procedure and, after removal of uncoupled segments and the trifluoroacetyl group, Ia was coupled followed again by removal of uncoupled segments. Final deblocking to remove citraconyl groups was accomplished under exceptionally mild conditions in aqueous acetic acid. The synthetic product was identical to natural alpha-IB-92 in amino acid analysis, HPLC, gel electrophoresis, and tryptic mapping. The synthetic peptide was indistinguishable from natural alpha-IB-92 in a radioimmunoassay and in an in vitro mouse pituitary assay for measuring suppression of FSH release in the presence of LHRH.
Blake, J Yamashiro, D Ramasharma, K Li, C H AM-6097/AM/NIADDK NIH HHS/ GM-2907/GM/NIGMS NIH HHS/ Denmark Int J Pept Protein Res. 1986 Nov;28(5):468-76.
The following values have no corresponding Zotero field: alt-title: International journal of peptide and protein research number: 5 edition: 1986/11/01 accession-num: 3102393 work-type: Comparative Study Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.
Keywords: Amino Acid Sequence; Animals; Mice; Indicators and Reagents; Male; Follicle Stimulating Hormone/secretion; Gonadotropin-Releasing Hormone/pharmacology; Inhibins/*chemical synthesis/pharmacology; Pituitary Gland/drug effects/secretion; Radioimmunoassay

Total synthesis of S-carbamoylmethyl bovine apocytochrome c by segment coupling - Blake, J. (Int. J. Pept. Protein Res., 1986)
Three peptide segments corresponding to the complete sequence of the 104 amino acid protein bovine apocytochrome c were synthesized by the solid-phase method. The peptides Ac-[Cys(Cam)14,17, GlyS23]-apocytochrome c-(1-23) (I), CF3CO-[GlyS60]-apocytochrome c-(24-60) (II), and CF3CO-apocytochrome c-(61-104) (III) were purified by chromatography on CM-cellulose, partition chromatography and/or HPLC. Each of the peptides was reacted with citraconic anhydride to block all of the lysine side chains, and the 61-104 peptide was treated with 10% hydrazine to remove the trifluoroacetyl group, to give the corresponding peptides Ia, IIa, and IIIa. Peptides IIa and IIIa were coupled together by reaction with silver nitrate/N-hydroxysuccinimide to give the 24-104 sequence. After removal of the trifluoroacetyl group from the amino terminus, peptide Ia was also coupled. Treatment of the peptide mixture with aqueous acetic acid removed the citraconyl groups, and purification by chromatography on CM-cellulose and HPLC gave a 0.6% yield of [Cys(Cam)14,17]-apocytochrome c. The synthetic product was shown to be identical to a sample derived from native bovine cytochrome c by paper or gel electrophoresis, HPLC and by chymotryptic or tryptic map.
Blake, J GM-2907/GM/NIGMS NIH HHS/ GM-30072/GM/NIGMS NIH HHS/ Denmark Int J Pept Protein Res. 1986 Feb;27(2):191-200.
The following values have no corresponding Zotero field: alt-title: International journal of peptide and protein research number: 2 edition: 1986/02/01 accession-num: 3009341 work-type: Research Support, U.S. Gov't, P.H.S.
Keywords: Amino Acid Sequence; Animals; Chromatography, High Pressure Liquid; Cattle; Indicators and Reagents; *Apoproteins; *Cytochromes c; Cytochrome c Group/*analogs & derivatives; Peptides/isolation & purification

Nuclear magnetic resonance studies of the solution chemistry of metal complexes. 23. Complexation of methylmercury by selenohydryl-containing amino acids and related molecules - Arnold, Alan P.; Tan, Khoon Sin; Rabenstein, Dallas L. (Inorg. Chem., 1986)
doi: 10.1021/ic00234a030 0020-1669 doi: 10.1021/ic00234a030
The following values have no corresponding Zotero field: number: 14 publisher: American Chemical Society

Cyclization under mild conditions of cysteine containing peptides - Zanotti, G.; Pinnen, F.; Lucente, G. (Tetrahedron Lett., 1985)
Cyclization of di- and tripeptides containing cysteine as N-terminal residue is reported. The preferred cyclization patterns and the nature of the products (diketopiperazine, aza-cyclol, peptide thiolactone) are discussed.
0040-4039
The following values have no corresponding Zotero field: number: 44

Stimulation of DNA synthesis in adult rat hepatocytes in primary culture by sera from patients with fulminant hepatic failure - Nakayama, H.; Tsubouchi, H.; Gohda, E.; Koura, M.; Nagahama, J.; Yoshida, H.; Daikuhara, Y.; Hashimoto, S. (Biomed. Res., 1985)
4 Biomedical research
Keywords: Adult animal; Animal adulte; Appareil digestif pathologie; Cell culture; Culture cellulaire; Digestive diseases; DNA synthesis; Foie voie biliaire pathologie; Fulminant; Hé Hepatobiliary disease; Hepatocyte; Homme; Human; Insuffisance hé Liver failure; Mammalia; patique; patocyte; Rat; Rodentia; rum; Sé se DNA; Serum; Stimulation; Synthè Vertebrata; #nosource

Solid phase synthesis (Nobel lecture) - Merrifield, Robert Bruce (Angew. Chem. Int. Ed., 1985)
The following values have no corresponding Zotero field: number: 10 publisher: Hüthig & Wepf Verlag
Keywords: Peptides; Solid-phase synthesis; Merrifield synthesis; Nobel lecture

On the source of intramolecular and enzymatic reactivity - Menger, F. M. (Acc. Chem. Res., 1985)
doi: 10.1021/ar00113a001 0001-4842 doi: 10.1021/ar00113a001
The following values have no corresponding Zotero field: number: 5 publisher: American Chemical Society

Dimethylaluminum methaneselenolate—a useful reagent for the preparation of selenoesters. A new friedel-crafts acylation procedure promoted by Cu(I) - Kozikowski, Alan P.; Ames, Anthony (Tetrahedron, 1985)
The preparation of a new aluminum reagent, dmiethylaluminum methaneselenolate (Me2AlSeMe) is described. The reactivity of this aluminum reagent toward a variety of organic substrates has been studied. Me2AlSeMe will convert O-alkyl esters to selenoesters in high yield. These selenoesters function as extremely reactive acyl transfer agents and are converted to acids, esters, and amides on reaction with water, alcohols or amines in the presence of a selenophilic metal cation. The selenoesters will, moreover, acylate reactive arenes and heterocyclic compounds when cuprous triflate is employed as the selenophilic metal cation. This latter transformation constitutes a new transition metal promoted variant of the Friedel-Crafts acylation reaction.
0040-4020
The following values have no corresponding Zotero field: number: 21

Diazapolycyclic compounds; XXV. Improved synthesis of 6-substituted 2,3-dihydrobenzo[g]phthalazine-1,4-dione derivatives - Campayo, L.; Jimenez, B.; Manzano, T.; Navarro, P. (Synthesis, 2002)
The following values have no corresponding Zotero field: number: 02 section: 197
Keywords: #nosource

A phosphate-catalysed acyl transfer reaction. Hydrolysis of 4-nitrophenyl acetate in phosphate buffers - O'Connor, C. J.; Wallace, R. G. (Aust. J. Chem., 1984)
The pseudo-first-order rate constants for the phosphate-catalysed hydrolysis of 4-nitrophenyl acetate have been determined in water at 310.5 K. The reaction has been followed spectrophotometrically by the disappearance of the ester and with n.m.r, spectroscopy by the appearance of both acetyl phosphate and the acetate ion and by the disappearance of ester. A phosphate-catalysed acyl transfer mechanism has been identified, in which the aryl ester is attacked by phosphate to give acetyl phosphate which is subsequently hydrolysed by water to acetate ion and regenerated catalyst. At concentrations of total phosphate exceeding 1.0 mol dm-3 the presence of dimeric phosphate species causes the appearance of a non-linear rate-concentration profile. Catalysis has been also been observed in 2,2'-(propane-1,3-diyldiimino)bis(propane-1,3-diol) buffer solutions.
The following values have no corresponding Zotero field: number: 12

Detergent effects on enzyme activity and solubilization of lipid bilayer membranes - Womack, M. D.; Kendall, D. A.; MacDonald, R. C. (Biochim. Biophys. Acta. Biomembranes, 1983)
Over 50 detergents were tested to establish which would be most effective in releasing proteins from membrane-bounded compartments without denaturing them. Various concentrations each of detergent were tested for two activities: (1) solubilization of egg phospholipid liposomes as measured by reduction of turbidity and (2) effect of detergent concentration on the activities of soluble, hydrolytic enzymes. Those detergents most effective in solubilizing 0.2% lipid and least detrimental to enzymes were five pure, synthetic compounds recently introduced: CHAPS, CHAPSO, Zwittergents 310 and 312, and octylglucoside. Industrial detergents were generally much inferior, insofar as they solubilized membranes inefficiently and/or inactivated certain hydrolytic enzymes readily. The five detergents were characterized by (a) an unusually high critical micelle concentration and (b) a preference for forming mixed micelles with lipids instead of forming pure micelles, as indicated by an ability to solubilize lipid at concentrations of detergent significantly below the critical micelle concentration. This characteristic permits solubilization of high concentrations of membrane below the critical micelle concentration of the detergent so that protein denaturation is minimized. A generally applicable guideline that emerged from this study is that detergents should be used at approximately their critical micelle concentration which should not be exceeded by the concentration of membrane. Similar considerations should apply to the use of detergents in purifying and reconstituting intrinsic membrane proteins.
GM 28404/GM/NIGMS NIH HHS/United States Comparative Study Journal Article Research Support, U.S. Gov't, P.H.S. Netherlands
The following values have no corresponding Zotero field: alt-title: Biochimica et biophysica acta number: 2 accession-num: 6882760
Keywords: Kinetics; Solubility; *Lipid Bilayers; Alkaline Phosphatase/*metabolism; Detergents/*pharmacology; Esterases/*metabolism; Phosphatidylcholines; Plants/enzymology; Sulfatases/*metabolism; Surface-Active Agents/*pharmacology; Triticum/enzymology

An SN2 deprotection of synthetic peptides with a low concentration of hydrofluoric acid in dimethyl sulfide: evidence and application in peptide synthesis - Tam, James P.; Heath, William F.; Merrifield, R. B. (J. Am. Chem. Soc., 2014)
The following values have no corresponding Zotero field: number: 21 publisher: American Chemical Society

The stabilities of various thiol compounds in protein purification - Stevens, R.; Stevens, L.; Price, N. C. (Biochem. Ed., 1983)
The following values have no corresponding Zotero field: number: 2
Keywords: #nosource

Effect of pH on the critical micelle concentration of sodium dodecyl sulphate - Rahman, A.; Brown, C. W. (J. Appl. Polym. Sci., 1983)
Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS) at various pH's between 2 and 10 has been studied using three methods as dye absorption, conductance, and light scattering measurement. At low pH (below pH 4) the CMC decreases whereas at higher pH it remains constant.
1097-4628
The following values have no corresponding Zotero field: number: 4 publisher: Wiley Subscription Services, Inc., A Wiley Company

Thiyl free radicals: direct observations of electron transfer reactions with phenothiazines and ascorbate - Forni, Luigi G.; Monig, Jorg; Mora-Arellano, Victor O.; Willson, Robin L. (J. Chem. Soc., Perkin Trans. 2, 1983)
Absolute rate constants for the reaction of the thiyl radicals derived from cysteamine, cysteine, glutathione, penicillamine, and 2-mercaptopropionylglycine (Thiola) with the phenothiazines, promethazine and chlorpromazine and with ascorbate ion, have been measured by pulse radiolysis and have been found to lie in the range 0.03-1.3 [times] 10 I mol s. The reactions are considered to occur by an electron transfer mechanism. The possibility that, in biochemical systems, glutathione can act as a catalyst linking hydrogen atom and electron transfer reactions is suggested.
0300-9580 10.1039/P29830000961
The following values have no corresponding Zotero field: number: 7 publisher: The Royal Society of Chemistry

Interaction of ascorbic acid with disulfides - Fleming, J. E.; Bensch, K. G. (Z. Naturforsch., 1983)
Keywords: #nosource

Improved deprotection in solid phase peptide synthesis: quantitative reduction of methionine sulfoxide to methionine during HF cleavage - Tam, James P.; Heath, William F.; Merrifield, R. B. (Tetrahedron Lett., 1982)
The following values have no corresponding Zotero field: number: 29

Improved deprotection in solid phase peptide synthesis: removal of protecting groups from synthetic peptides by an SN2 mechanism with low concentrations of HF in dimethylsulfide - Tam, James P.; Heath, William F.; Merrifield, R. B. (Tetrahedron Lett., 1982)
The following values have no corresponding Zotero field: number: 43

Quantum chemical studies of a model for peptide bond formation: formation of formamide and water from ammonia and formic acid - Oie, Tetsuro; Loew, Gilda H.; Burt, Stanley K.; Binkley, J. Stephen; MacElroy, Robert D. (J. Am. Chem. Soc., 1982)
doi: 10.1021/ja00387a001 0002-7863 doi: 10.1021/ja00387a001
The following values have no corresponding Zotero field: number: 23 publisher: American Chemical Society

Implications for in vitro studies of the autoxidation of ferrous ion and the iron-catalyzed autoxidation of dithiothreitol - Lambeth, D. O.; Ericson, G. R.; Yorek, M. A.; Ray, P. D. (Biochim. Biophys. Acta, 1982)
Biochim Biophys Acta 0006-3002
The following values have no corresponding Zotero field: number: 3
Keywords: Dithiothreitol; Iron

Enzymatic condensation of nonassociated peptide fragments using a molecular trap - Homandberg, G. A.; Komoriya, A.; Chaiken, I. M. (Biochemistry, 1982)
We have tested the feasibility of achieving protease-catalyzed condensation between nonassociating peptide fragments through mediation of a molecular trap. In this study, two subfragments of bovine pancreatic ribonuclease S-peptide, containing residues 1-10 and 11-15, were rejoined by clostripain catalysis to form the 1-15 peptide. The extent of this stereospecific condensation was enhanced by adding ribonuclease S-protein (residues 21-124), which acts as a trap in binding 1-15 but not 1-10 or 11-15 and which thus shifts the equilibrium to favor 1-15 formation. The resultant (1-15) X (21-124) noncovalent complex, defined as [des-16-20]ribonuclease S, was detected by the enzymatic activity characteristic of the naturally derived ribonuclease S complex. Reaction of 1 mM S-protein and 20 mM fragments leads to 80% of the ribonuclease activity expected from the amount of 21-124 present. This indicates that 4% of the fragments 1-10 and 11-15 were condensed, compared to a maximal condensation of 5% based on the amount of trap. The less than theoretical yield is due largely to slow proteolytic degradation of 21-124 to a form which is no longer able to bind the condensation product 1-15. Yields were increased to 15% by addition of further trap. The successful synthesis of 1-15 emphasizes the usefulness of molecular traps to promote stereospecific fragment condensation between nonassociating peptide fragments for the synthesis and semisynthesis of polypeptides.
Journal Article United States
The following values have no corresponding Zotero field: alt-title: Biochemistry number: 14 accession-num: 7052121
Keywords: Animals; Cattle; Methods; Endopeptidases/metabolism; Amino Acids/analysis; *Cysteine Endopeptidases; Peptide Fragments/isolation & purification/*metabolism; Ribonucleases/*analysis/metabolism

Infrared and Raman spectra of S-methyl thioacetate: toward an understanding of the biochemical reactivity of esters of coenzyme A - El-Aasar, A. M.; Nash, C. P.; Ingraham, L. L. (Biochemistry, 1982)
The infrared and Raman spectra of S-methyl thioacetate and CD3C(O)SCH3 have been determined. These spectra and those in the literature ofr S-ethyl thioacetate have been assigned. These data together with literature assignments for thioformic acid, thioacetic acid, and S-methyl thioformate were used in normal coordinate calculations. The stretching force constant for the carbonyl group of thioesters and thio acids is found to be very similar to that for the carboxyl group of ketones. In addition, the value of the stretching force constant for the C(O)-S bond in thioesters and thio acids indicates that this entity has no double-bond character. The carbonly group of acetyl coenzyme A is essentially the same as that of a ketone.
Journal Article United States
The following values have no corresponding Zotero field: alt-title: Biochemistry number: 8 accession-num: 7082657
Keywords: Spectrophotometry, Infrared; *Acetates; Spectrum Analysis, Raman

Ring closure reactions of bifunctional chain molecules - Illuminati, Gabriello; Mandolini, Luigi (Acc. Chem. Res., 1981)
doi: 10.1021/ar00064a001 0001-4842 doi: 10.1021/ar00064a001
The following values have no corresponding Zotero field: number: 4 publisher: American Chemical Society

Sulfhydryl group protection in peptide synthesis - Hiskey, R. G. (The Peptides. Analysis, Synthesis, Biology. Vol 3, 1981)
Keywords: #nosource

The path of chemical reactions - the IRC approach - Fukui, Kenichi (Acc. Chem. Res., 1981)
doi: 10.1021/ar00072a001
The following values have no corresponding Zotero field: number: 12 publisher: American Chemical Society

Leaving group effects in thiolester hydrolysis. Part 2. On the possibility of an elimination-addition (keten) mediated pathway in S-acetylcoenzyme a basic hydrolysis and acetyl transfer - Douglas, Kenneth T.; Yaggi, Norbert F.; Mervis, Cynthia M. (J. Chem. Soc., Perkin Trans. 2, 1981)
Alkaline hydrolysis rates () at 25 [degree]C in aqueous solution for a series of -alkyl and -aryl thiolacetates, including -acetylcoenzyme A, were correlated (as their logarithms) with the p of the conjugate acid of the thiolate leaving group to give a slope ([small beta]) of -0.33. In comparison with the corresponding oxygen esters, thiolesters are, for the basicity of a given leaving species, one to two orders of magnitude less reactive towards hydroxide ion and show little dispersion into aryl and alkyl leaving groups, ascribed to the lower steric sensitivity of thiolacetate esters compared with the oxygen analogues. The small value of [small beta] and the lower reactivity of - than -esters are offered as evidence of a bimolecular associative (2) mechanism for basic hydrolysis. The 2 route is excluded by the lack of deuterium incorporation into the (acetate) product of hydrolysis. In spite of the accepted acidity of thiolacetates, a kinetically insignificant amount of ester conjugate base is formed in aqueous solution even at high, non-physiological pH and thus -acetylcoenzyme A does not hydrolyse by an 1cB pathway.
0300-9580 10.1039/P29810000171
The following values have no corresponding Zotero field: number: 1 publisher: The Royal Society of Chemistry

On relative leaving abilities: use of isobasic plots to determine the relative nucleofugalities of thiolates and their oxy-analogues - Douglas, Kenneth T.; Alborz, Manoochehr (Chem. Commun., 1981)
The use of an isobasic plot shows that, when structures are analogous and pa values identical, RO departs from acetoacetate ester anions 5 [times] 10 times faster than RS and 79 times faster from fluorene-9-carboxylic acid ester anions, a reversal of the apparent order of nucleofugality determined by measured rates of elimination of RS and RO.
0022-4936 10.1039/C39810000551
The following values have no corresponding Zotero field: number: 11 publisher: The Royal Society of Chemistry

New segment-coupling method for peptide synthesis in aqueous solution: application to synthesis of human [Gly17]-beta-endorphin - Blake, J.; Li, C. H. (Proc. Natl. Acad. Sci. U. S. A., 1981)
The thiolcarboxyl peptide [17-thiolglycine]-beta-endorphin-(1-17) (I) was synthesized by the solid-phase method. Reaction of peptide I with citraconic anhydride gave citraconyl-[Lys(Cit9,GlyS17]-beta-endorphin-(1-17) (Ia). Peptide Ia was coupled to another synthetic peptide, [Lys(Cit)19,24,28,29]-beta-endorphin-(18-31), by reaction with silver nitrate--N-hydroxysuccinimide in water. All citraconyl groups were removed in aqueous acetic acid, and [Gly17]-beta-endorphin was isolated in 30-40% yield. The synthetic analog had 10% analgesic potency and 59% opiate--receptor binding activity when compared with human beta-endorphin.
Blake, J Li, C H GM-2907/GM/NIGMS NIH HHS/United States MH-30245/MH/NIMH NIH HHS/United States Research Support, U.S. Gov't, P.H.S. United states Proceedings of the National Academy of Sciences of the United States of America Proc Natl Acad Sci U S A. 1981 Jul;78(7):4055-8.
The following values have no corresponding Zotero field: number: 7 edition: 1981/07/01 accession-num: 6270658
Keywords: Amino Acid Sequence; Animals; Humans; Mice; Structure-Activity Relationship; Methods; Biological Assay; beta-Endorphin; Endorphins/*chemical synthesis; Oligopeptides/*chemical synthesis; Pain/physiopathology

Peptide segment coupling in aqueous medium: silver ion activation of the thiolcarboxyl group - Blake, J. (Int. J. Pept. Protein Res., 1981)
The use of the thiolcarboxyl function for the assemblage of deblocked peptide segments in aqueous medium has been investigated. The C-terminal thiolcarboxyl peptide Ac-Tyr-Arg-Arg-Glu-Arg-Gly-SH (2a) has been synthesized by the solid-phase method. The silver compound of peptide 2a was coupled to H-Phe-Ala-Glu-Gly-OH in 50% aqueous dimethylformamide to give a 40% yield of Ac-Tyr-Arg-Arg-Glu-Arg-Gly-Phe-Ala-Glu-Gly-OH.
Blake, J AM-18677/AM/NIADDK NIH HHS/United States AM-6097/AM/NIADDK NIH HHS/United States GM-2907/GM/NIGMS NIH HHS/United States Research Support, U.S. Gov't, P.H.S. Denmark International journal of peptide and protein research Int J Pept Protein Res. 1981 Feb;17(2):273-4.
The following values have no corresponding Zotero field: number: 2 edition: 1981/02/01 accession-num: 7228502
Keywords: Amino Acid Sequence; Oligopeptides/*chemical synthesis; *Silver

Reaction progress at the transition state for nucleophilic attack on esters - Kovach, Ildiko M.; Elrod, James P.; Schowen, Richard L. (J. Am. Chem. Soc., 1980)
doi: 10.1021/ja00545a023 0002-7863 doi: 10.1021/ja00545a023
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

Formation of C–S Bond by the elimination of perfluorocarboxylic acid - Kawa, H.; Ishikawa, N. (Bull. Chem. Soc. Jpn., 1980)
Keywords: #nosource

Ring-closure reactions. 14. Kinetics of macrocyclization by the intramolecular acylation of thiophene and benzothiophene compounds - Galli, C.; Illuminati, G.; Mandolini, L. (J. Org. Chem., 1980)
doi: 10.1021/jo01290a022 0022-3263 doi: 10.1021/jo01290a022
The following values have no corresponding Zotero field: number: 2 publisher: American Chemical Society

Substrate specificity of a proteolytic enzyme isolated from a mutant of Pseudomonas fragi - Drapeau, G. R. (J. Biol. Chem., 1980)
Previous studies have described the isolation of mutationally altered proteases in Pseudomonas fragi (Noreau, J., and Drapeau, G.R. (1979) J. Bacteriol, 140, 911-916. In the present study, it is shown that one of these proteases cleaves specifically the peptide bonds on the NH2-terminal side of either aspartic acid or cysteic acid residues in oxidized ribonuclease. With myoglobin as the substrate, a similar specificity was observed except that only four out of the six aspartyl bonds present were hydrolyzed.
0021-9258 (Print) 0021-9258 (Linking) Journal Article
The following values have no corresponding Zotero field: number: 3 accession-num: 7188696
Keywords: Animals; Humans; Substrate Specificity; Amino Acids/analysis; Myoglobin; Peptide Fragments/analysis; Peptide Hydrolases/*metabolism; Pseudomonas/*enzymology; Ribonucleases; Whales

Leaving group effects in thiolester alkaline hydrolysis. Part 1. A keten-mediated (E1 cB) pathway for basic hydrolysis of S-acetoacetylcoenzyme A and analogues - Douglas, Kenneth T.; Yaggi, Norbert F. (J. Chem. Soc., Perkin Trans. 2, 1980)
The basic hydrolysis of a series of leaving-group substituted acetothiolacetates (CHCOCHCOSR) has been studied in aqueous media. Hydrolysis of -acetyl--acetoacetylcysteamine follows a kinetic ionisation curve with an inflexion corresponding to the p of this ester as determined by spectrophotometric and electrometric titrations. The rate constant at high pH was shown to follow a Bronsted relationship with [small beta]-1.13, where [small beta] is the slope of a plot of the logarithm of the rate constant the p of the conjugate acid of the leaving group. This, and other evidence from rate comparisons, activation parameters, and kinetic solvent isotope effects, indicated an 1 cB hydrolytic mechanism involving unimolecular collapse of the ester enolate ions a ketenoid transition-state. -Acetoacetylcoenzyme A was also hydrolysed in base by this mechanism. Direct comparison of rates of leaving group expulsion for ArS and ArO was possible by means of this unimolecular process. For a leaving group with p 10, the oxyanion departs . 1 or 2 orders of magnitude faster than the thiolate anion; for p 6.0, the advantage of oxygen over sulphur is 10-10 fold. In a direct structural comparison, PhS departs 32 times as rapidly as PhO. The contribution of steric release in the 1 cB transition-state for -t-butyl acetothiolacetate hydrolysis is discussed. The p values of some acetothiolacetates were measured.
0300-9580 10.1039/P29800001037
The following values have no corresponding Zotero field: number: 7 publisher: The Royal Society of Chemistry

Ring-closure reactions. Part 15. Solvent effects on cyclic aralkyl ether formation by intramolecular Williamson synthesis - Cort, Antonella Dalla; Illuminati, Gabriello; Mandolini, Luigi; Masci, Bernardo (J. Chem. Soc., Perkin Trans. 2, 1980)
Product analysis, rate data, and effective molarity (e.m.) values have been obtained for the formation of catechol polymethylene ethers by the intramolecular alkylation of -[small omega]-bromoalkoxyphenoxides in MeSO-water (99 : 1, v/v). Twelve ring sizes were investigated in the range 6-32. Comparison with similar data for the reaction in EtOH-water (75 : 25, v/v)(except for 32) showed that the e.m. values are largely independent of solvent despite the large solvent effect observed in both the cyclization reaction and the related intermolecular model reaction. Small effects only were observed in the medium ring region. The main possible factors playing a role in solvent effects on intramolecular cyclization have been critically analysed in the light of the data.
0300-9580 10.1039/P29800001774
The following values have no corresponding Zotero field: number: 12 publisher: The Royal Society of Chemistry

Organoselenium chemistry. Dealkylation of amines with benzeneselenol - Reich, Hans J.; Cohen, Martin L. (J. Org. Chem., 1979)
doi: 10.1021/jo01332a012 0022-3263 doi: 10.1021/jo01332a012
The following values have no corresponding Zotero field: number: 18 publisher: American Chemical Society

The azide method in peptide synthesis - Meienhofer, J. (The Peptides. Analysis, Synthesis, Biology. Vol 1, 1979)
Keywords: #nosource

Ring-closure reactions. 12. gem-dimethyl effect in some medium and large rings - Galli, Carlo; Giovannelli, Giuseppe; Illuminati, Gabriello; Mandolini, Luigi (J. Org. Chem., 1979)
doi: 10.1021/jo01322a015 0022-3263 doi: 10.1021/jo01322a015
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

General-base-catalyzed intramolecular aminolysis of thiol esters. Cyclization of S-n-propyl o-(2-imidazolyl)thiolbenzoate. Relationship of the uncatalyzed and base-catalyzed nucleophilic reactions - Fife, Thomas H.; DeMark, B. R. (J. Am. Chem. Soc., 1979)
doi: 10.1021/ja00518a041 0002-7863 doi: 10.1021/ja00518a041
The following values have no corresponding Zotero field: number: 24 publisher: American Chemical Society

Practical synthesis of cyclic peptides, with an example of dependence of cyclization yield upon linear sequence - Brady, Stephen F.; Varga, Sandor L.; Freidinger, Roger M.; Schwenk, Debra A.; Mendlowski, Michael; Holly, Frederick W.; Veber, Daniel F. (J. Org. Chem., 1979)
doi: 10.1021/jo01332a003 0022-3263 doi: 10.1021/jo01332a003
The following values have no corresponding Zotero field: number: 18 publisher: American Chemical Society

Synthesis of polyamides from active 2-benzothiazolyl dithiolesters and diamines under mild conditions - Ueda, Mitsuru; Sato, Akira; Imai, Yoshio (J. Polymer Sci., 1978)
Novel examples were presented of the use in polyamide synthesis of active 2-benzothiazolyl dithiolesters for which aminolysis is assisted by a neighboring group. Solution polycondensation of new dithiolesters, 2,2′-(adipoyldithio)bisbenzothiazole and 2,2′-(isophtahloyldithio)bisbenzothiazole, with both aliphatic and aromatic diamines in polar aprotic solvents (N-methyl-2-pyrrolidone and hexamethylphosphoramide) took place rapidly at room temperature yielding polyamides with high molecular weight. The interfacial polycondensation in a chloroform–water system was also successful for polyamide formation. S,S′-Di-p-nitrophenyl dithioisophthalate reacted much more slowly toward diamines than the 2-benzothiazolyl dithiolesters. Prior to polymer synthesis, the aminolysis of active monothiolesters was carried out as a model compound study.
1542-9369
The following values have no corresponding Zotero field: number: 2 publisher: John Wiley & Sons, Inc.

Synthesis of substance P via its sulfoxide by the repetitive excess mixed anhydride (REMA) method - Izeboud, E.; Beyerman, H. C. (Rec. Trav. Chim., 1978)
The N-protected heptapeptide sulfoxide corresponding to positions 5 to 11 inclusive of substance P, Boc-Gln-Gln-Phe-Phe-Gly-Leu-Met(O)-NH2(VII), was synthesized by the repetitive excess mixed anhydride (REMA) method (Scheme). Consecutive mixed anhydride coupling to N-deprotected VII of the dipeptides Boc-Lys(Z)-Pro-OH (VIII) and Z-Arg(NO2)-Pro-OH (X) yielded protected substance P sulfoxide, XI. From XI both Z groups and the NO2 group were removed with liquid hydrogen fluoride, yielding substance P sulfoxide. Substance P sulfoxide was conveniently reduced to substance P with the aid of iodide ions in strongly acid olution. Preliminary results are given on the scope of this method, i.e. peptides containing - besides methionine - tyrosine, where the method worked well, or tryptophan, where the method failed. REMA-synthesized substance P, after gel filtration, was found to be chemically pure and to possess the same biological activity as a substance P standard (Beckman), according to two tests (sialagogic assay and guinea pig ileum contraction).
0165-0513
The following values have no corresponding Zotero field: number: 1 publisher: WILEY-VCH Verlag

A mild procedure for solid phase peptide synthesis: use of fluorenylmethoxycarbonylamino-acids - Atherton, E.; Fox, Hazel; Harkiss, Diana; Logan, C. J.; Sheppard, R. C.; Williams, B. J. (J. Chem. Soc. Chem. Commun., 1978)
The following values have no corresponding Zotero field: publisher: The Royal Society of Chemistry

Structure-reactivity correlations for the thiol-disulfide interchange reaction - Wilson, Janet M.; Bayer, Robert J.; Hupe, D. J. (J. Am. Chem. Soc., 1977)
doi: 10.1021/ja00466a027 0002-7863 doi: 10.1021/ja00466a027
The following values have no corresponding Zotero field: number: 24 publisher: American Chemical Society

Rates of thiol-disulfide interchange reactions between mono- and dithiols and Ellman's reagent - Whitesides, George M.; Lilburn, Jennifer E.; Szajewski, Richard P. (J. Org. Chem., 1977)
doi: 10.1021/jo00422a034 0022-3263 doi: 10.1021/jo00422a034
The following values have no corresponding Zotero field: number: 2 publisher: American Chemical Society

Reactivity of sulfhydryl group in peptides and polypeptides with p-nitrophenylacetate. S to N acyl shift in cysteine. - Trudelle, Yves; Caille, Anita (Int. J. Pept. Protein Res., 1977)
The activity of poly (Cys-Ser-Phe-Glu-Glu) and related polypeptides as models of cysteine-proteases towards p-nitrophenylacetate was studied. The reaction leads to the formation of an S-acetylated form which proved to be quite stable, except at very high pH values. The presence of imidazole groups in the neighbourhood of sulfhydryl functions seems to result in an enhancement of the activity, which we attributed to a cooperative interaction. However, this interaction has no effect upon the S-deacylation rate. In the case of cysteine we found that the reaction with NPA occurred through a S to N acyl shift. Our results lead us to suggest that, unless convincing proofs of deacylation are given, the various models of cysteine-proteases studied so far do not behave as “true catalysts”.
1399-3011
The following values have no corresponding Zotero field: number: 4 publisher: Blackwell Publishing Ltd
Keywords: acyl shift in cysteine-peptides-polypeptides-reactivity of sulfhydryl group

Activation of thiol esters. Partial synthesis of cytochalasins A and B - Masamune, Satoru; Hayase, Yoshio; Schilling, Walter; Chan, Wan Kit; Bates, Gordon S. (J. Am. Chem. Soc., 1977)
The following values have no corresponding Zotero field: number: 20 publisher: American Chemical Society

Nonlinear structure-reactivity correlations. Acyl transfer between sulfur and oxygen nucleophiles - Hupe, D. J.; Jencks, W. P. (J. Am. Chem. Soc., 1977)
null
doi: 10.1021/ja00444a023 0002-7863 doi: 10.1021/ja00444a023
The following values have no corresponding Zotero field: number: 2 publisher: American Chemical Society

Intramolecular catalysis of acylation and deacylation in peptides containing cysteine and histidine - Heller, Michael J.; Walder, Joseph A.; Klotz, Irving M. (J. Am. Chem. Soc., 1977)
doi: 10.1021/ja00450a060 0002-7863 doi: 10.1021/ja00450a060
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Ring-closure reactions. 7. Kinetics and activation parameters of lactone formation in the range of 3- to 23-membered rings - Galli, Carlo; Illuminati, Gabriello; Mandolini, Luigi; Tamborra, Pasquale (J. Am. Chem. Soc., 1977)
doi: 10.1021/ja00450a031 0002-7863 doi: 10.1021/ja00450a031
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Effect of detergents on the S- to N-acyl transfer of S-acyl-b-mercaptoethylamines - Cuccovia, Iolanda M.; Schroeter, Elsie H.; De Baptista, Roberto C.; Chaimovich, Hernan (J. Org. Chem., 1977)
doi: 10.1021/jo00441a016 0022-3263 doi: 10.1021/jo00441a016
The following values have no corresponding Zotero field: number: 21 publisher: American Chemical Society

Pteridines. XXXVII. A total synthesis of L-erythro-biopterin and some related 6-(polyhydroxyalkyl)pterins - Taylor, Edward C.; Jacobi, Peter A. (J. Am. Chem. Soc., 1976)
doi: 10.1021/ja00424a051 0002-7863 doi: 10.1021/ja00424a051
The following values have no corresponding Zotero field: number: 8 publisher: American Chemical Society

Cytochalasin B (Phomin): Abbaureaktionen und Cyclisierung der B-Cytochalasinsäure zu 21,22-Dihydro-isocytochalasin A - Scherling, Dietrich; Csendes, Ivan; Tamm, Christoph (Helv. Chim. Acta, 1976)
Cytochalasin B (Phomin): Degradation Reactions and Cyclization of B-Cytochalasinic Acid to 21,22-Dihydro-Isocytochalasin A Treatment of the γ-lacton 5, a transformation product of cytochalasin B (phomin) (1), with OsO4 gave the dihydroxy derivatives 6 and 7. Cleavage of the former by NaIO4 in aqueous methanol yielded a mixture of the dimethylacetal 10 and the unsaturated aldehyde 11, which are potential intermediates for a total synthesis of cytochalasins. Cytochalasin B (1) was hydrolysed with NaOH in aqueous dioxane to B-cytochalasinic acid (14). Recyclization of 14 using the Mukaiyama-Corey method [19] [20] did not yield cytochalasin B (1) but the isomeric 21,22-dihydro-isocytochalasin A (18). Treatment of 14 according to Gerlach [21] yielded the phthalimidine 19.
The following values have no corresponding Zotero field: number: 3 publisher: WILEY-VCH Verlag GmbH

Affinity purification of synthetic peptides - Krieger, D. E.; Erickson, B. W.; Merrifield, R. B. (Proc .Natl. Acad. Sci. U. S. A., 1976)
A general strategy and a specific tactic for affinity purification of polypeptides synthesized on solid supports are desbribed and demonstrated. The desired peptide chains were distinguished from terminated peptide chains before removal from the support by attachment of an affinity reagnet (cysteinyl-methionine) bearing an affinity group (thiol) and a binding group (carboxylic acid). After cleavage from the synthetic support, the affinity-labeled peptides (Cys-Met-peptides) were bound to an affinity receptor (organomercurial-agarose) and thus separated from terminated peptides and all other peptides lacking the affinity group. The desired synthetic peptide was obtained by separation of the affinity reagent (loss of Cys-Met by cyanogen bromide cleavage). This general affinity purification strategy is independent of the length or amino acid sequence of the desired peptide. After assembly of ribonuclease-(111-124)-tetradecapeptide, using radiolabeled acetic anhudride for termination of uncoupled in termediates, essentially all (greater than 98.5%) of the acetylated delection peptides were removed by employing the organomercurial Cys-Met tactic. Similarly, the purity of crude synthetic histone H4-(1-37)-heptatriacontapeptide was increased six-fold by using this tactic to remove terminated peptides. A related dimeric Cys-Met tactic is outlined for affinity purification of peptides containing internal cysteine and methionine residues.
0027-8424 (Print) 0027-8424 (Linking) Journal Article Research Support, U.S. Gov't, P.H.S.
The following values have no corresponding Zotero field: number: 9 accession-num: 1067609
Keywords: Peptides/chemical synthesis/*isolation & purification; Cysteine; Amino Acids/analysis; Ribonucleases; Chromatography, Affinity; Histones; Methionine

A new micro-test for the detection of incomplete coupling reactions in solid-phase peptide synthesis using 2,4,6-trinitrobenzenesulphonic acid - Hancock, W. S.; Battersby, J. E. (Anal. Biochem., 1976)
Hancock, W S Battersby, J E United states Analytical biochemistry Anal Biochem. 1976 Mar;71(1):260-4.
The following values have no corresponding Zotero field: number: 1 edition: 1976/03/01 accession-num: 1275229
Keywords: Peptides/*chemical synthesis; *Nitrobenzenes; *Trinitrobenzenesulfonic Acid; Coloring Agents; Microchemistry; Ninhydrin

Photochemistry of organochalcogen compounds. 2. Photochemical deselenation of benzyl diselenide by triphenylphosphine - Chu, Joseph Y. C.; Marsh, Dana G. (J. Org. Chem., 1976)
doi: 10.1021/jo00881a031 0022-3263 doi: 10.1021/jo00881a031
The following values have no corresponding Zotero field: number: 19 publisher: American Chemical Society

Some pertinent aspects of mechanism as determined with small molecules - Bruice, T. C. (Annu. Rev. Biochem., 1976)
Journal Article Review United States
The following values have no corresponding Zotero field: alt-title: Annual review of biochemistry accession-num: 786153
Keywords: Kinetics; Molecular Conformation; Protein Binding; Thermodynamics; Structure-Activity Relationship; Binding Sites; X-Ray Diffraction; Chemical Phenomena; Chemistry; *Coenzymes/metabolism; *Enzymes/metabolism; Acyltransferases/metabolism; Carboxy-Lyases/metabolism; Esterases/metabolism; Muramidase/metabolism; Pyridoxal; Transaminases/metabolism

Peptide synthesis from the practitioner's point of view - Veber, D. F. (Peptides: Chemistry, Structure and Biology. Proceeding of the fourth american peptide symposium, 1975)
Keywords: #nosource

The methylsulfonylethyloxycarbonyl group, a new and versatile amino protective function - Tesser, G. I.; Balvert-Geers, I. C. (Int. J. Pept. Protein Res., 1975)
The following values have no corresponding Zotero field: number: 4 edition: 1975/01/01 accession-num: 241727
Keywords: Hydrogen-Ion Concentration; Amino Acids; Binding Sites; Peptides/*chemical synthesis; Indicators and Reagents; *Sulfones/chemical synthesis

Syntheses of macrolide antibiotics. III. Direct ester and lactone synthesis from S-tert-butyl thioate (thiol ester) - Masamune, Satoru; Kamata, Susumu; Schilling, Walter (J. Am. Chem. Soc., 1975)
The following values have no corresponding Zotero field: number: 12 publisher: American Chemical Society

Rapid intramolecular acyl transfer from phenol to carbinolamine-progress toward a new class of peptide coupling reagent - Kemp, D. S.; Vellaccio, F. (J. Org. Chem., 1975)
Kemp, D S Vellaccio, F Jr J Org Chem. 1975 Oct 3;40(20):3003-4.
The following values have no corresponding Zotero field: alt-title: The Journal of organic chemistry number: 20 edition: 1975/10/13 accession-num: 1177079 work-type: Research Support, U.S. Gov't, P.H.S.
Keywords: Acylation; Indicators and Reagents; *Peptides; Chemical Phenomena; Chemistry; Acetophenones; Benzaldehydes; Benzylamines

Peptide bond formation by the amine capture principle - Kemp, D. S.; Grattan, J. A.; Reczek, J. (J. Org. Chem., 1975)
Kemp, D S Grattan, J A Reczek, J J Org Chem. 1975 Nov 14;40(23):3465-6.
The following values have no corresponding Zotero field: alt-title: The Journal of organic chemistry number: 23 edition: 1975/11/14 accession-num: 1185322 work-type: Research Support, U.S. Gov't, P.H.S.
Keywords: Peptides/*chemical synthesis; Chemical Phenomena; Chemistry; *Amines

In vitro reaction of b-propiolactone and g-butyrolactone with glutathione and cysteine - Dijkstra, J. (Chem.-Biol. Interactions, 1975)
0009-2797
The following values have no corresponding Zotero field: number: 2

Selenium abstraction from diethyl diselenide by tertiary phosphines - Cross, Ronald J.; Millington, Douglas (J. Chem. Soc. Chem. Commun., 1975)
The photochemical deselenation of EtSe by PhMeP proceeds by an EtSe[middle dot] radical chain mechanism to form EtSe and PhMePSe in high yield.
0022-4936 10.1039/C39750000455
The following values have no corresponding Zotero field: number: 11 publisher: The Royal Society of Chemistry

Solubilization of bacterial membrane proteins using alkyl glucosides and dioctanoyl phosphatidylcholine - Baron, C.; Thompson, T. E. (Biochim. Biophys. Acta. Biomembranes, 1975)
The non-ionic detergent octyl glucoside solubilizes a substantial amount of Streptococcus faecalis membrane protein without loss of the monitored enzyme activities. A secondary detergent, dioctanoyl phophatidycholine, appears to increase the yield of solubilized material. In addition, the effect of ionic strength indicates that it may be possible to selectively extract groups of membrane proteins by their characteristic solubility at different ionic strengths. The solubilized membrane-associated enzymes, ATPase and NADH dehydrogenase, enter polyacrylamide gels as distict species. Electrophoretic studies suggest that there are two membrane-associated ATPase in the Streptococcus faecalis, one which dissociates from the membrane in the absence of Mg-2+ ions and the other which remains particulate until solubilized by detergents. Octyl glucoside can be easily removed from a solution containing solubilized proteins and lipid by dialysis.
Journal Article Research Support, U.S. Gov't, P.H.S. Netherlands
The following values have no corresponding Zotero field: alt-title: Biochimica et biophysica acta number: 3 accession-num: 123771
Keywords: Protein Binding; Methods; Solubility; Osmolar Concentration; *Glucosides; *Glycosides; *Phosphatidylcholines; Adenosine Triphosphatases/analysis; Bacterial Proteins/*isolation & purification; Cell Membrane/enzymology; Detergents; Enterococcus faecalis/analysis/enzymology; NADH, NADPH Oxidoreductases/analysis; Polyethylene Glycols

Synthese der Schafinsulin-A-Kette mit 6–11-Disulfidring, I - Wittinghofer, Alfred (Liebigs Ann. Chem., 1974)
Die für eine Synthese der Schafinsulin-A-Kette mit 6–11 -Disulfidring benötigten Fragmente A 1–5 (5), A 6–12[SS] (16, 17), A 13–21 (26), A 1–l2[SS] (27) und A 6–21[SS] (28) werden beschrieben. Als selektiv nebeneinander abspaltbare Schwefelschutzgruppen ermöglichen die Tetrahydropyranyl(Thp)- und Äthylcarbamoylgruppe (EC) den Aufbau der Fragmente 5, 16, 17 und 26 unter Verwendung der N(o-Nitrophenyl)sulfenyl(Nps)- und N-Tritylschutzgruppe (Trt) sowie der Schutzgruppen vom tert.-Butyltyp. In Gegenwart von S-Thpund 0-tert.-Butylschutzgruppen ist für die selektive Abspaltung der Nps-Gruppe Zusatz von Indol erforderlich. Die S-Äthylcarbamoylgruppen des Fragmentes der Sequenz A 6–12 (15) werden mit methanolischem Ammoniak selektiv neben der S-Thp-Gruppe abgespalten wodurch das Dithiol entsteht. Die Oxidation des Dithiols mit Dijodäthan liefert das monomere cyclische Disulfid 16 oder 17. Synthesis of the A-Chain of Ovine Insulin with a 6-11-Disulfide Loop The fragments necessary for synthesis of the ovine insulin A-chain with a 6–11-disulfide loop A 1–5 (5), A 6–12[SS] (16,17), A 13–21 (26), A 1–12[SS] (27), and A 6–21[SS] (28) are described. As selective sulfur protecting groups, which can be removed independently, the tetrahydropyranyl(Thp)- and the ethylcarbamoyl group (EC) permit the synthesis of the fragments 5,16,17 and 26 with application of the N-(o-nitropheny1)sulfenyl (Nps) and N-trityl (Trt) protecting groups, as well as protecting groups of the tert.-butyl type. In the presence of the S-Thp and 0-tert.-butyl protecting groups, the selective removal of the Nps group requires the addition of indole. The S-ethylcarbamoyl groups of the fragment A 6–12 (15) were selectively converted to the dithiol in the presence of the S-Thp group. The oxidation of the dithiol with diiodoethane yields the cyclic disulfide monomer 16 or 17.
1099-0690
The following values have no corresponding Zotero field: number: 2 publisher: WILEY-VCH Verlag

Rearrangements involving thiols - Sheradsky, Tuvia (The Thiol Group (1974), 1974)
This chapter contains sections titled: * Introduction * Group Migrations from and onto Thiols * Rearrangements of the O-Thioacyl System to the S-Acyl System * The Thio-Claisen Rearrangement * Internal Additions, Eliminations and Ring-chain Tautomerisms * Miscellaneous Rearrangements * References
9780470771327
Keywords: alkyl groups; biochemical processes; quantitative yield; rearrangement reactions; sulphide ion

Mechanism of the aminolysis of acetate esters - Satterthwait, Arnold C.; Jencks, William P. (J. Am. Chem. Soc., 1974)
doi: 10.1021/ja00829a034 0002-7863 doi: 10.1021/ja00829a034
The following values have no corresponding Zotero field: number: 22 publisher: American Chemical Society

Urea and guanidine hydrochloride denaturation of ribonuclease, lysozyme, alpha-chymotrypsin, and beta-lactoglobulin - Greene, R. F.; Pace, C. N. (J. Biol. Chem., 1974)
Comparative Study Journal Article United States
The following values have no corresponding Zotero field: alt-title: The Journal of biological chemistry number: 17 accession-num: 4416801
Keywords: Animals; Protein Conformation; Kinetics; Hydrogen-Ion Concentration; Protein Binding; Thermodynamics; Binding Sites; Spectrophotometry, Ultraviolet; *Protein Denaturation; Disulfides; Urea; Female; Guanidines; Chemical Phenomena; Chemistry, Physical; *Chymotrypsin; *Lactoglobulins; *Muramidase; *Ribonucleases; Calorimetry; Goats; Mathematics; Optical Rotation; Pregnancy

Bildung von Estern und Lactonen durch Silberionen-Katalyse - Gerlach, Hans; Thalmann, Adolf (Helv. Chim. Acta, 1974)
A mild and efficient method for the preparation of esters has been found in the silver ion induced reaction of alcohols with 2-pyridyl esters of thiocarboxylic S-acids. Examples are given to show the utility of this push button activation for the rapid formation of macrocyclic lactones and esters at room temperature under non-basic conditions.
The following values have no corresponding Zotero field: number: 8 publisher: WILEY-VCH Verlag GmbH

Polarographic reduction of diphenyldiselenide at DME - Fagioli, F.; Pulidori, F.; Bighi, C.; De Battisti, A. (Gazz. Chim. Ital., 1974)
Keywords: #nosource

(untitled) - Fagioli, F.; Pulidori, F.; Bighi, C.; De Battisti, A. (Gazz. Chim. Ital., 1974)
Keywords: #nosource

Efficient and mild lactonization method for the synthesis of macrolides - Corey, E. J.; Nicolaou, Kyriacos C. (J. Am. Chem. Soc., 1974)
The following values have no corresponding Zotero field: number: 17 publisher: American Chemical Society

Mechanistische Untersuchung zur Acyl-Übertragung von Thioestern auf Amino- und Imidazolgruppen - Wenck, Helmut; Polster, Jürgen (Helv. Chim. Acta, 1973)
Die Reaktion von 4′-Mercapto-acetanilid-acetat mit n-Butylamin sowie mit Imidazol wurde bei pH 7,5 und 25,0° mit Hilfe von Reaktionsspektren, Extinktionsdifferenzen-Diagrammen und Extinktionsdifferenzen-Quotienten-Diagrammen untersucht. Die Aminolyse des Thioesters ist «spektroskopisch einheitlich», die Imidazolyse verläuft in zwei linear unabhängigen Reaktionen: Bildung und Hydrolyse von N-Acetyl-imidazol. Durch formale Integration wurden die Geschwindigkeitskonstanten pseudo-erster Ordnung ermittelt. Unter physiologischen Bedingungen verläuft die Imidazolyse schneller, bei Berücksichtigung der pK-Werte muss jedoch das Amin als reaktiver betrachtet werden.
1522-2675
The following values have no corresponding Zotero field: number: 6 publisher: WILEY-VCH Verlag GmbH

Discussion des modes normaux des groupements amides cis et trans à partir des champs de force du s-valérolactame et du N-methylacetamide - Rey-Lafon, M.; Forel, M. T.; Garrigou-Lagrange, C. (Spectrochim. Acta, 1973)
Valence force fields of Ïƒ-valerolactam and N methylacetamide are determined. The normal modes of characteristic vibrations of cis and trans amide groups are specially discussed. This comparison shows the existence of an interaction between oxygen and hydrogen in the amide cis group.
0584-8539
The following values have no corresponding Zotero field: number: 3

Compounds structurally related to complexone I. Tris(carboxyethyl)phosphine - Podlaha, J.; Podlahova, J. (Collect. Czech. Chem. Commun., 1973)
Keywords: #nosource

Selenol esters as specific reagents of the acylation of thiol groups - Makriyannis, Alexandros; Guenther, Wolfgang H. H.; Mautner, Henry G. (J. Am. Chem. Soc., 1973)
doi: 10.1021/ja00806a033 0002-7863 doi: 10.1021/ja00806a033
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

Polypeptides. LII. Synthesis of a cysteine protected peptide amide corresponding to positions 81-104 of the ribonuclease T1 sequence - Kawasaki, Koichi; Gamble, Roger; Dupuis, Gilles; Romovacek, Hana; Storey, Harold T.; Yanaihara, Chizuko; Hofmann, Klaus (J. Am. Chem. Soc., 1973)
doi: 10.1021/ja00801a048 0002-7863 doi: 10.1021/ja00801a048
The following values have no corresponding Zotero field: number: 20 publisher: American Chemical Society

Ring-closure reactions. I. Kinetics of lactone formation in the range of seven- to twelve-membered rings - Galli, Carlo; Illuminati, Gabriello; Mandolini, Luigi (J. Am. Chem. Soc., 1973)
doi: 10.1021/ja00806a028 0002-7863 doi: 10.1021/ja00806a028
The following values have no corresponding Zotero field: number: 25 publisher: American Chemical Society

Thermodynamic acid dissociation constants of aromatic thiols - De Maria, Paolo; Fini, Adamo; Hall, Francis M. (J. Chem. Soc., Perkin Trans. 2, 1973)
The thermodynamic acid dissociation constants of thiophenol and a series of - and -substituted thiophenols have been measured in water at 25[degree]C by the e.m.f.-spectrophotometric method. The results and the significance of the linear free energy relationship for thiophenols are discussed and compared with the limited data available in the literature.
0300-9580 10.1039/P29730001969
The following values have no corresponding Zotero field: number: 14 publisher: The Royal Society of Chemistry

Intramolecular catalysis and the involvement of tetrahedral intermediate partitioning in the hydrolysis of benzoylcholine, benzoylthionocholine, and their dimethylamino analogs - Bruice, Paula Yurkanis; Mautner, Henry G. (Journal of the American Chemical Society, 1973)
doi: 10.1021/ja00786a037 0002-7863 doi: 10.1021/ja00786a037
The following values have no corresponding Zotero field: number: 5 publisher: American Chemical Society

Acetamidomethyl. A Novel thiol protecting group for cysteine - Veber, Daniel; Milkowski, John; Varga, Sandor; Denkewalter, Robert; Hirschmann, Ralph (J. Am. Chem. Soc., 1972)
doi: 10.1021/ja00770a600 0002-7863 doi: 10.1021/ja00770a600
The following values have no corresponding Zotero field: number: 15 publisher: American Chemical Society

Polypeptides. LI. Application of S-ethylcarbamoylcysteine to the synthesis of a protected heptatetracontapeptide related to the primary sequence of ribonuclease T1 - Storey, Harold T.; Beacham, John; Cernosek, Stanley F.; Finn, Frances M.; Yanaihara, Chizuko; Hofmann, Klaus (J. Am. Chem. Soc., 1972)
doi: 10.1021/ja00772a040 0002-7863 doi: 10.1021/ja00772a040
The following values have no corresponding Zotero field: number: 17 publisher: American Chemical Society

General acid-base catalysis of complex reactions in water - Jencks, William P. (Chem. Rev., 1972)
doi: 10.1021/cr60280a004 0009-2665 doi: 10.1021/cr60280a004
The following values have no corresponding Zotero field: number: 6 publisher: American Chemical Society

N,N-disubstituted aminoethylcarbamyl protecting groups for cysteine - Jäger, G.; Geiger, R.; Hoechst (1972)
The following values have no corresponding Zotero field: tertiary-authors: N,N-disubstituted aminoethylcarbamyl protecting groups for cysteine volume: US 3679655 A number: US 3679655 A
Keywords: #nosource

Kinetics of the reaction of 2,4-dinitro-1-fluorobenzene with imidazole-SH-, and imidazole-SH-compounds - Voigt, R.; Wenck, H.; Schneider, F. (Z. Naturforsch B, 1971)
Journal Article Germany
The following values have no corresponding Zotero field: alt-title: Zeitschrift fur Naturforschung number: 10 orig-pub: Kinetik der Reaktion von 2,4-Dinitrofluorbenzol mit Imidazol-, SH- und Imidazol-SH-Verbindungen. accession-num: 4401623
Keywords: Kinetics; Hydrogen-Ion Concentration; *Fluorenes; Chemical Phenomena; Chemistry; *Nitrobenzenes; *Hydrocarbons, Halogenated; *Imidazoles; *Sulfhydryl Compounds; Dinitrophenols; Hydrogen Sulfide

The role of intramolecular bifunctional catalysis of ester hydrolysis in water - Maugh II, T.; Bruice, T. C. (J. Am. Chem. Soc., 1971)
Keywords: #nosource

Normal coordinate analysis of some esters; Methyl formate, methyl acetate and dimethyl oxalate - Matzke, P.; Chacon, O.; Andrade, C. (J. Mol. Struct., 1971)
Keywords: #nosource

Amino-acids and peptides. Part XXXIV. Anchimerically assisted coupling reactions: the use of 2-pyridyl thiolesters - Lloyd, K.; Young, G. T. (J. Chem. Soc. C, 1971)
Further examples are presented of the use in peptide synthesis of esters for which aminolysis is assisted by a neighbouring group. 2-Pyridyl thiolesters of phthaloyl-, benzyloxycarbonyl-, and t-butoxycarbonyl-amino-acids are described, and it is shown that they condense very rapidly even with hindered amino-esters to give high yields of protected dipeptides. Phthaloyl--phenylalanine pyrimidin-2-yl thiolester is also described. No racemisation could be detected when t-butoxycarbonyl--valine 2-pyridyl thiolester condensed with -valine methyl ester, even in the presence of triethylamine. The thiolesters reacted slowly with alcohols, and ethyl -t-butoxycarbonylglycylglycolate and --lactate were so prepared. In contrast to the usual solvent dependence for the aminolysis of active esters, the rate of condensation of t-butoxycarbonyl--leucine 2-pyridyl thiolester with -anisidine increases when the solvent is changed from dimethyl sulphoxide to dimethylformamide and then to dioxan or ethyl acetate.
0022-4952 10.1039/J39710002890
The following values have no corresponding Zotero field: number: 0 publisher: The Royal Society of Chemistry

The safety catch principle in solid phase peptide synthesis - Kenner, G. W.; McDermott, J. R.; Sheppard, R. C. (J. Chem. Soc. D Chem. Commun., 1971)
N-Protected amino-acid active esters react readily with polystyrenesulphonamide yielding, after deprotection, the poly(aminoacylsulphonamides): these polymers are suitable for solid phase peptide synthesis, the completed peptide being cleaved from the resin by methylation and hydrolysis or aminolysis.
The following values have no corresponding Zotero field: number: 12 publisher: The Royal Society of Chemistry

Equilibrium deuterium isotope effects on the ionization of thiol acids - Jencks, William P.; Salvesen, Karin (J. Am. Chem. Soc., 1971)
doi: 10.1021/ja00747a016 0002-7863 doi: 10.1021/ja00747a016
The following values have no corresponding Zotero field: number: 18 publisher: American Chemical Society

Acyl-transfer reactions of amides and esters with alcohols and thiols. Reference system for the serine and cysteine proteinases. Nitrogen protonation of amides and amide-imidate equilibriums - Fersht, Alan R. (J. Am. Chem. Soc., 1971)
doi: 10.1021/ja00743a035 0002-7863 doi: 10.1021/ja00743a035
The following values have no corresponding Zotero field: number: 14 publisher: American Chemical Society

Reactions of hydroxylamine with acetoacetyl thioesters or ethyl acetoacetate - Schulz, H.; Wakil, S. J. (Anal. Biochem., 1970)
Journal Article United States
The following values have no corresponding Zotero field: alt-title: Analytical biochemistry number: 2 accession-num: 5476200
Keywords: Hydrogen-Ion Concentration; Esters; Methods; Spectrophotometry; Chemical Phenomena; Chemistry; *Acetoacetates; *Hydroxylamines; Chromatography, Thin Layer; Oxazoles; Oximes; Sulfur

Reduction and racemization of sulfoxides by halide ions in aqueous perchloric acid - Modena, Giorgio; Landini, Dario; Montanari, Fernando; Scorrano, Gianfranco (J. Am. Chem. Soc., 1970)
doi: 10.1021/ja00727a024 0002-7863 doi: 10.1021/ja00727a024
The following values have no corresponding Zotero field: number: 24 publisher: American Chemical Society

The preparation of α-amino-α-benzylmercaptopropionic acid derivatives - Kaneda, A.; Sudo, R. (Bull. Chem. Soc. Jpn., 1970)
The following values have no corresponding Zotero field: number: 7
Keywords: #nosource

The normal vibrations of formic acid and methyl formate - Susi, S.; Scherer, J. R. (Spectrochim. Acta, 1969)
Keywords: #nosource

Kinetics of the reaction of imidazole-SH-compounds with N-ethylmaleimide - Schneider, F.; Wenck, H. (Hoppe-Seylers Z. Physiol. Chem., 1969)
Journal Article Germany
The following values have no corresponding Zotero field: alt-title: Hoppe-Seyler's Zeitschrift fur physiologische Chemie number: 12 orig-pub: Kinetik der Reaktion von Imidazol-SH-Verbindungen mit N-Athyl-maleinimid. accession-num: 5363654
Keywords: Kinetics; Hydrogen-Ion Concentration; Chemical Phenomena; Chemistry; *Imidazoles; *Sulfhydryl Compounds; *Cysteine; *Ethylmaleimide; *Glutathione

pH dependence of ester hydrolysis catalyzed by imidazolethiol compounds - Schneider, F.; Wenck, H. (Hoppe-Seylers Z. Physiol. Chem., 1969)
Journal Article Germany
The following values have no corresponding Zotero field: alt-title: Hoppe-Seyler's Zeitschrift fur physiologische Chemie number: 12 orig-pub: pH-Abhangigkeit der durch Imidazol-SH-Verbindungen katalysierten Esterhydrolyse. accession-num: 5363660
Keywords: Kinetics; Esters; Chemical Phenomena; Chemistry; *Imidazoles; *Sulfhydryl Compounds; *Catalysis; *Hydrogen-Ion Concentration; Phenylacetates

Reduction of biological substances by water-soluble phosphines: gamma-globulin (IgG) - Levison, M. E.; Josephson, A. S.; Kirschenbaum, D. M. (Experientia, 1969)
Journal Article Switzerland
The following values have no corresponding Zotero field: alt-title: Experientia number: 2 accession-num: 4182166
Keywords: Humans; Chromatography, Gel; *Phosphines; Chemical Phenomena; Chemistry; *gamma-Globulins; Agglutination Tests; Blood Protein Electrophoresis; Latex; Mercaptoethanol; Microspheres; Rheumatoid Factor/antagonists & inhibitors

Cyclic disulfides. II. 1,2-Dithiepan-5-amine - Herbrandson, H. F.; Wood, R. H. (J Med Chem, 1969)
Herbrandson, H F Wood, R H United states Journal of medicinal chemistry J Med Chem. 1969 Jul;12(4):617-20.
The following values have no corresponding Zotero field: number: 4 edition: 1969/07/01 accession-num: 5793150
Keywords: Oxidation-Reduction; Amines/*chemical synthesis; Iodine; Radiation-Protective Agents/*chemical synthesis; Sulfides/*chemical synthesis

Cyclic disulfides. 3. (--)-(S)-1,2-Diethiepan-4-amine and related compounds - Herbrandson, H. F.; Wood, R. H. (J. Med. Chem., 1969)
Herbrandson, H F Wood, R H United states Journal of medicinal chemistry J Med Chem. 1969 Jul;12(4):620-4.
The following values have no corresponding Zotero field: number: 4 edition: 1969/07/01 accession-num: 5793151
Keywords: Amines/*chemical synthesis; Radiation-Protective Agents/*chemical synthesis; Sulfides/*chemical synthesis

Computed circular dichroism spectra for the evaluation of protein conformation - Greenfield, N.; Fasman, G. D. (Biochemistry, 1969)
Greenfield, N Fasman, G D United states Biochemistry Biochemistry. 1969 Oct;8(10):4108-16.
The following values have no corresponding Zotero field: number: 10 edition: 1969/10/01 accession-num: 5346390
Keywords: X-Ray Diffraction; Spectrum Analysis; Carboxypeptidases/analysis; Chymotrypsin/analysis; Computers; Enzyme Precursors/analysis; Lysine/analysis; Muramidase/analysis; Myoglobin/analysis; Optical Rotatory Dispersion; Proteins/*analysis; Ribonucleases/analysis

An investigation of racemisation during the use of acetoacetyl-L-valine in peptide synthesis - Di Bello, Carlo; Filira, Fernando; Giormani, Virgilio; D'Angeli, Ferruccio (J. Chem. Soc. C, 1969)
The following values have no corresponding Zotero field: number: 3 publisher: The Royal Society of Chemistry

Oxazolinone intermediates in the hydrolysis of activated N-acylamino acid esters. The relevance of oxazolinones to the mechanism of action of serine proteinases - De Jersey, J.; Willadsen, P.; Zerner, B. (Biochemistry, 1969)
Journal Article United States
The following values have no corresponding Zotero field: alt-title: Biochemistry number: 5 accession-num: 5785217
Keywords: Kinetics; Hydrogen-Ion Concentration; Esters; Buffers; Drug Stability; Spectrophotometry; *Amino Acids; Chemical Phenomena; Chemistry; *Endopeptidases; *Hippurates; *Nitrophenols; *Oxazoles; Imidazoles; Phosphates; Serine

Diffusion-controlled proton transfer in intramolecular thiol ester aminolysis and thiazoline hydrolysis - Barnett, Ronald E.; Jencks, William P. (J. Am. Chem. Soc., 2014)
doi: 10.1021/ja01037a029
The following values have no corresponding Zotero field: number: 9 publisher: American Chemical Society

Further studies on the concerted imidazole-thiol catalysis - Schneider, F.; Schaich, E.; Wenck, H. (Hoppe-Seylers Z. Physiol. Chem., 1968)
Journal Article Germany
The following values have no corresponding Zotero field: alt-title: Hoppe-Seyler's Zeitschrift fur physiologische Chemie number: 11 orig-pub: Weitere Untersuchungen zur kooperativen Imidazol-SH-Katalyse. accession-num: 5745903
Keywords: Hydrogen-Ion Concentration; Esters; Thermodynamics; *Imidazoles; *Sulfhydryl Compounds; *Cysteine; *Catalysis; *Phenylacetates

Nucleophilic reactivity constants toward methyl iodide and trans-[Pt(py)2Cl2] - Pearson, R. G.; Sobel, H.; Songstag, J. (J. Am. Chem. Soc., 1968)
Keywords: #nosource

The use of acylamino-acid esters of 2-mercaptopyridine in peptide synthesis - Lloyd, K.; Young, G. T. (Chem. Commun., 1968)
0009-241X 10.1039/C1968001400B
The following values have no corresponding Zotero field: number: 22 publisher: The Royal Society of Chemistry

Nonlinear structure-reactivity correlations. The reactivity of nucleophilic reagents toward esters - Jencks, William P.; Gilchrist, Mary (J. Am. Chem. Soc., 1968)
doi: 10.1021/ja01012a030 0002-7863 doi: 10.1021/ja01012a030
The following values have no corresponding Zotero field: number: 10 publisher: American Chemical Society

Acidic dissociation constants of thiols - Danehy, James P.; Parameswaran, K. N. (J. Chem. & Eng. Data, 1968)
doi: 10.1021/je60038a025 0021-9568 doi: 10.1021/je60038a025
The following values have no corresponding Zotero field: number: 3 publisher: American Chemical Society

Rate-limiting diffusion-controlled proton transfer in an acetyl transfer reaction - Barnett, R.; Jencks, W. P. (J. Am. Chem. Soc., 2014)
doi: 10.1021/ja01017a076
The following values have no corresponding Zotero field: number: 15 publisher: American Chemical Society

Syntheses and pharmacological properties of selenium isologs of oxytocin and deaminooxytocin - Walter, Roderich; Chan, Wah-Yip (J. Am. Chem. Soc., 1967)
The following values have no corresponding Zotero field: number: 15 publisher: American Chemical Society

The standard redox potential of cysteine-cystine from the thiol-disulphide exchange reaction with glutathione and lipoic acid - Jocelyn, P. C. (Eur. J. Biochem., 1967)
Thiol-disulphide exchange between glutathione (GSH) and cystine (CSSC) or oxidised glutathione (GSSG) and cysteine (CSH) has been followed by assaying GSH and GSSG specifically at low pH during the reaction. Velocity and equilibrium constants have been derived. From the latter and the known standard oxidation-reduction potential (E0′) of GSH/GSSG, E0′ (pH 7) of CSH/CSSC is found to be -0.22 volt. The course of the reaction of both these pairs with dihydrolipoic acid/lipoic acid has been inferred from absorbance changes at 330 mμ. Results confirm that their E0′ values are considerably more positive than for the dihydrolipoic acid/lipoic acid system.
The following values have no corresponding Zotero field: number: 3 publisher: Blackwell Publishing Ltd

Comparison of the chemical properties of selenocysteine and selenocystine with their sulfur analogs - Huber, R. E.; Criddle, R. S. (Arch. Biochem. Biophys., 1967)
The following values have no corresponding Zotero field: alt-title: Archives of biochemistry and biophysics number: 1 accession-num: 6076213
Keywords: Temperature; Hydrogen-Ion Concentration; Models, Chemical; Drug Stability; Solubility; Spectrophotometry; *Sulfur; Chemical Phenomena; Chemistry; *Cysteine; *Cystine; *Organometallic Compounds; *Selenium; Polarography