Showing papers by "Volker Kasche published in 1991"
TL;DR: Results show that organic molecules bound to the enzyme surface perturb the P1′-S1′ interactions and change the catalytic properties of the enzyme.
Abstract: In kinetically controlled peptide synthesis catalyzed by α-chymotrypsin (EC 3.4.21.1, CT) the P1′-specificity and stereospecificity was found to increase for hydrophobic and decrease for positively charged nucleophiles in systems with hydrophobic organic solvent molecules. This was observed in the following systems: (i) buffer saturated with organic solvent molecules; (ii) the enzyme adsorbed on a hydrophobic adsorbent (Phenylbutylamine-Eupergit). These results show that organic molecules bound to the enzyme surface perturb the P1′-S1′ interactions and change the catalytic properties of the enzyme.
33 citations
TL;DR: The alpha-chymotrypsin-catalyzed acyl transfer to a series of glycine oligomers was investigated and it could be established that the electrostatic interactions between the carboxylate group of the nucleophiles and the S'-subsites of the enzyme fall off with the length of the nucleus.
15 citations
TL;DR: This work describes a video camera based technique which allows both the sensitive detection and determination of the spatial distribution of luminescent Streptomyces coelicolor pellets and filaments within liquid and soil samples.
Abstract: The successful cloning of the bioluminescence genes from marine bacteria offers the chance to use the bioluminescence phenotype as a marker for environmental monitoring purposes. This work describes a video camera based technique which allows both the sensitive detection and determination of the spatial distribution of luminescent Streptomyces coelicolor pellets and filaments within liquid and soil samples.
6 citations
Journal Article•
TL;DR: The analysis of the structure-activity relationships of the hydrophobic S1'-P1' contact indicates that the S1' subsite can accommodate maximally three methyl(ene) groups and hydrophilic amino acid side chains are better bound to S2' than can be explained by theirhydrophobicities.
Abstract: The ratio of hydrolysis to aminolysis product in papain-catalyzed acyl transfer reactions using various nucleophiles was determined. The data are interpreted in terms of binding specificity. The acyl transfer reactions were performed using the acyl donor Mal-Phe-Ala-OEtCl. The analysis of the structure-activity relationships of the hydrophobic S1'-P1' contact indicates that the S1' subsite can accommodate maximally three methyl(ene) groups. Hydrophilic amino acid side chains are better bound to S1' than can be explained by their hydrophobicities. The S2' as well as the S3' binding subsite exhibits a preference for space-filling hydrophobic amino acid residues.
5 citations
Journal Article•
TL;DR: The sequence- and stereospecificity of the S1- and S' i-subsites of bovine alpha-chymotrypsin and trypsin, proteinase K and penicillin amidase from E. coli and A. viscosus has been determined by hydrolysis and kinetically controlled peptide synthesis using different substrates.
Abstract: The sequence- and stereospecificity of the S1- and S' i-subsites (i = 1-3) of bovine alpha-chymotrypsin and trypsin, proteinase K and penicillin amidase from E. coli and A. viscosus has been determined by hydrolysis and kinetically controlled peptide synthesis using different substrates. The data are compared with results for other serine proteases and the thiol protease papain. The stereospecificities differ by orders of magnitude, decreased when the enzyme was immobilized and were influenced when organic solvent molecules were bound to the enzyme.
4 citations