Biochemical characterization of the carbapenem-hydrolyzing beta-lactamase AsbM1 from Aeromonas sobria AER 14M: a member of a novel subgroup of metallo-beta-lactamases.
AsbM1, a carbapenem-hydrolyzing beta-lactamase produced by Aeromonas sobria AER 14M, was purified chromatographically, with anion exchange chromatography performed in the absence of Zn2+. The molecular mass of AsbM1 was approximately 34,000; the isoelectric point was 9.1. AsbM1 had high hydrolytic specificity for carbapenems but low hydrolysis rates for penicillins and cephalosporins. AsbM1 was resistant to the commercially available beta-lactamase inhibitors but was inhibited by pCMB and the chelators EDTA and o-phenanthroline. Zinc, an activator for many metallo-beta-lactamases, inhibited AsbM1 with an IC50 of 8 microM. Analysis of the N-terminal sequence (27 amino acids) showed 26% similarity to the CphA metallo-beta-lactamase. Because of the high specificity for carbapenems and the sensitivity to inhibition by Zn2+, AsbM1 should be included in a new subgroup of metallo-beta-lactamases.
Yang
Y
Y
Wyeth-Ayerst Research, Lederle Laboratories, Pearl River, NY 10965, USA.
Bush
K
K
D000333:Aeromonas / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D015780:Carbapenems / Q000378:metabolism*; D006868:Hydrolysis; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D015780:Carbapenems; D001618:beta-Lactamases