title: Cephalosporin-sensitive penicillin-binding proteins of Staphylococcus aureus and Bacillus subtilis active in the conversion of [14C]penicillin G to [14C]phenylacetylglycine.
abstract: Breakdown of the covalent complex formed between [14C]penicillin G and higher molecular weight, cephalosporin-sensitive penicillin-binding proteins was studied using mixtures of the purified proteins isolated from membranes of Staphylococcus aureus and Bacillus subtilis. These penicillin-binding proteins were found to release the bound 14C label in a first order process characterized by half-lives of 10 to 300 min at 37 degrees C. Denaturation of the penicilloyl.penicillin-binding proctein complex prevented this release, indicating that the process is enzyme-catalyzed. [14C]Phenylacetylglycine was identified as the major labeled fragmentation product, indicating that these cephalosporin-sensitive penicillin-binding proteins, for which no in vitro transpeptidase or carboxypeptidase activity has been found, catalyze the same fragmentation of the bound penicilloyl moiety previously described for several penicillin-sensitive D-alanine carboxypeptidases.
mesh_terms: D001409:Bacillus cereus / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002511:Cephalosporins / Q000494:pharmacology*; D005998:Glycine / Q000031:analogs & derivatives*; D007700:Kinetics; D010400:Penicillin G / Q000378:metabolism*; D010406:Penicillins / Q000378:metabolism*; D010648:Phenylacetates; D013045:Species Specificity; D013211:Staphylococcus aureus / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D002511:Cephalosporins; D010406:Penicillins; D010648:Phenylacetates; C022050:phenylacetylglycine; D010400:Penicillin G; D005998:Glycine