title: An inducible beta-lactamase in a strain of Escherichia coli.
abstract: The production of beta-lactamase (penicillin/cephalosporin beta-lactam amidohydrolase, E.C.3.5.2.6) was found to be inducible in a clinically isolated strain of Escherichia coli. This is the first report of an inducible beta-lactamase in E. coli. The optimal concentration of inducer was 400 mug/ml of ml of benzylpenicillin, or 800 mug/ml of 6-aminopenicillanic acid. About fiftyfold induction was achieved. Maximum induction took ninety minutes from the time of adding the inducer. Induction was abolished by the presence of chloramphenicol(10 mug/ml). The enzyme has a molecular wieght of 23,000, and is inhibited by rho-chloromercuribenzoate and by iodine. It is active against a wide range of substrates, including cephaloridine and cloxacillin.
mesh_terms: D002701:Chloramphenicol / Q000494:pharmacology; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003023:Cloxacillin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000494:pharmacology; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007455:Iodine / Q000494:pharmacology; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D008712:Methicillin / Q000494:pharmacology; D008970:Molecular Weight; D010068:Oxacillin / Q000378:metabolism; D010397:Penicillanic Acid / Q000494:pharmacology; D010400:Penicillin G / Q000494:pharmacology; D010405:Penicillinase / Q000378:metabolism*
chemical_list: D002729:Chloromercuribenzoates; D008623:Mercaptoethanol; D002701:Chloramphenicol; D010397:Penicillanic Acid; D007455:Iodine; D004492:Edetic Acid; D010405:Penicillinase; D003023:Cloxacillin; D010400:Penicillin G; D008712:Methicillin; D010068:Oxacillin