title: DD-Carboxypeptidase activity of membrane fragments of Mycobacterium smegmatis. Enzymatic properties and sensitivity to beta-lactam antibiotics.
abstract: A DD-carboxypeptidase activity is present in membrane fragments of Mycobacterium smegmatis. Kinetic parameters of the enzymatic activity have been studied using UDP-N-glycolylmuramyl-L-alanyl-gamma-D-glutamyl-meso-2,2'-diaminopimelyl-D-[14C]alanyl-D-[14C]alanine as substrate. The DD-carboxypeptidase can be solubilized by Triton X-100 and Genapol X-100. It is inhibited by beta-lactam antibiotics although intact cells of M. smegmatis are insensitive to that kind of antibiotics. Inhibition by penicillin G is slowly reversible. By storage, at -20degrees C, kinetic parameters and sensitivity to penicillin G vary non-concomittantly, suggesting a penicillin binding site different from the substrate binding site.
mesh_terms: D002268:Carboxypeptidases / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002511:Cephalosporins / Q000494:pharmacology*; D007700:Kinetics; D002267:Muramoylpentapeptide Carboxypeptidase / Q000378:metabolism*; D009161:Mycobacterium / Q000187:drug effects / Q000201:enzymology*; D010406:Penicillins / Q000494:pharmacology*
chemical_list: D002511:Cephalosporins; D010406:Penicillins; D002268:Carboxypeptidases; D002267:Muramoylpentapeptide Carboxypeptidase