title: Peptide inhibitors of Streptomyces DD-carboxypeptidases.
abstract: 1. Peptides that inhibit the dd-carboxypeptidases from Streptomyces strains albus G and R61 were synthesized. They are close analogues of the substrates of these enzymes. The enzymes from albus G and R61 strains are in general inhibited by the same peptides, but the enzyme from strain R39 differs considerably. 2. The two C-terminal residues of the peptide substrates and inhibitors appear to be mainly responsible for the initial binding of the substrate to the enzymes from albus G and R61 strains. The side chain in the third residue from the C-terminus seems critical in inducing catalytic activity. 3. Experimental evidence is presented suggesting that the amide bond linking the two C-terminal residues has a cis configuration when bound to the enzymes from strains albus G and R61. 4. The peptide inhibitors are not antibiotics against the same micro-organisms.
mesh_terms: D002247:Carbon Isotopes; D002268:Carboxypeptidases / Q000037:antagonists & inhibitors*; D002852:Chromatography, Ion Exchange; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D004590:Electrophoresis, Paper; D007700:Kinetics; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D009904:Optical Rotation; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*
chemical_list: D002247:Carbon Isotopes; D009842:Oligopeptides; D002268:Carboxypeptidases