title: Purification and characterization of a new beta-lactamase from Bacteroides uniformis.
abstract: A beta-lactam-resistant Bacteroides uniformis strain was isolated from a clinical specimen. The strain produced large amounts of beta-lactamase and was resistant to penicillins and cephalosporins. The specific activity of the unpurified beta-lactamase was 4.8 U/mg of protein with nitrocefin as the substrate. The enzyme was purified 188-fold by Q-Sepharose, Sephacryl S-300, and Mono Q column passages. Kinetic parameters of the enzyme were determined by a micromethod performed in microtiter plates. beta-Lactamase was inhibited by cefoxitin and imipenem and hydrolyzed cephalosporins more rapidly than penicillins. The molecular weight was determined by sodium dodecyl sulfate-gradient gel electrophoresis to be 32,500, and the isoelectric point was 4.5.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D001439:Bacteroides / Q000201:enzymology*; D007526:Isoelectric Point; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases