title: Streptomyces R61 DD-carboxypeptidase: hydrolysis of X-D-alanyl-D-alanine peptides measured by a fluorometric assay.
abstract: A fluorometric procedure for measuring the activity of DD-carboxypeptidase is described. The method is based on the reaction of one of the products, D-alanine, with o-phthaldialdehyde to form a highly fluorescent adduct. The method has been applied in examining a series of X-D-alanyl-D-alanine peptides as substrates of the penicillin-sensitive DD-carboxypeptidase from Streptomyces R61. The effect of the third residue, X, on kinetic parameters and its implications on the steric analog model for penicillin action are also discussed.
mesh_terms: D000409:Alanine / Q000032:analysis; D002268:Carboxypeptidases / Q000032:analysis*; D005470:Fluorometry; D006868:Hydrolysis; D007700:Kinetics; D002267:Muramoylpentapeptide Carboxypeptidase / Q000032:analysis* / Q000378:metabolism; D010406:Penicillins / Q000494:pharmacology; D010452:Peptide Biosynthesis; D010455:Peptides / Q000378:metabolism*; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity; D009764:o-Phthalaldehyde
chemical_list: D010406:Penicillins; D010455:Peptides; D009764:o-Phthalaldehyde; D002268:Carboxypeptidases; D002267:Muramoylpentapeptide Carboxypeptidase; D000409:Alanine