title: Evidence for an oxyanion hole in serine beta-lactamases and DD-peptidases.
abstract: A thionocephalosporin is shown to be a much poorer substrate of representative serine beta-lactamases of class A (RTEM-2) and class C (Enterobacter cloacae P99) and a much poorer inhibitor of the Streptomyces R61 DD-peptidase than is the analogous oxo beta-lactam. These results provide kinetic evidence for the existence of a catalytic oxyanion hole in these enzymes.
authors.affiliation: Department of Chemistry, Wesleyan University, Middletown, CT 06457.
authors.forename: B P
authors.initials: BP
authors.lastname: Murphy
authors.forename: R F
authors.initials: RF
authors.lastname: Pratt
mesh_terms: D002268:Carboxypeptidases / Q000378:metabolism*; D002511:Cephalosporins / Q000378:metabolism; D004754:Enterobacter / Q000201:enzymology; D006868:Hydrolysis; D007700:Kinetics; D015335:Molecular Probes; D010447:Peptide Hydrolases / Q000378:metabolism*; D011487:Protein Conformation; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D002511:Cephalosporins; D015335:Molecular Probes; D002268:Carboxypeptidases; D010447:Peptide Hydrolases; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; D001618:beta-Lactamases; C056342:beta-lactamase TEM-2