title: Purification and characterization of an extracellular beta-lactamase produced by Acinetobacter calcoaceticus.
abstract: A beta-lactamase was purified 430-fold from the culture supernatant of Acinetobacter calcoaceticus by ion exchange chromatography on CM-Sephadex and affinity chromatography on phenylboronic-acid-agarose. The purified enzyme was homogeneous as judged by SDS-PAGE, and was characterized with respect to molecular mass (38 and 41 kDa by gel filtration on Sephadex G-75 and SDS-PAGE, respectively), pH optimum (pH 7.0), temperature optimum (45 degrees C) and isoelectric point (9.3). The beta-lactamase showed mainly cephalosporinase activity. It was inhibited by cloxacillin, carbenicillin, penicillanic acid sulphone (sulbactam) and aztreonam. It was not inhibited by clavulanic acid up to a concentration of 0.25 mM. Neither EDTA nor p-chlormercuribenzoate, up to concentrations of 1 or 100 mM, respectively, affected activity. According to these characteristics, it is a typical CEP-N cephalosporinase.
authors.affiliation: Bereich Biochemie, Sektion Biowissenschaften, Universität Leipzig, Federal Republic of Germany.
authors.forename: B
authors.initials: B
authors.lastname: Blechschmidt
authors.forename: P
authors.initials: P
authors.lastname: Borneleit
authors.forename: H P
authors.initials: HP
authors.lastname: Kleber
mesh_terms: D016954:Acinetobacter calcoaceticus / Q000201:enzymology*; D002228:Carbenicillin / Q000494:pharmacology; D002510:Cephalosporinase / Q000302:isolation & purification / Q000378:metabolism; D002512:Cephalothin / Q000378:metabolism; D003023:Cloxacillin / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D065093:beta-Lactamase Inhibitors; D002510:Cephalosporinase; D001618:beta-Lactamases; D002228:Carbenicillin; D003023:Cloxacillin; D002512:Cephalothin