title: Kinetic properties of four plasmid-mediated AmpC beta-lactamases.
abstract: The heterologous production in Escherichia coli, the purification, and the kinetic characterization of four plasmid-encoded class C beta-lactamases (ACT-1, MIR-1, CMY-2, and CMY-1) were performed. Except for their instability, these enzymes are very similar to the known chromosomally encoded AmpC beta-lactamases. Their kinetic parameters did not show major differences from those obtained for the corresponding chromosomal enzymes. However, the K(m) values of CMY-2 for cefuroxime, cefotaxime, and oxacillin were significantly decreased compared to those of the chromosomal AmpC enzymes. Finally, the susceptibility patterns of different E. coli hosts producing a plasmid- or a chromosome-encoded class C enzyme toward beta-lactam antibiotics are mainly due to the overproduction of the beta-lactamase in the periplasmic space of the bacteria rather than to a specific catalytic profile of the plasmid-encoded beta-lactamases.
authors.affiliation: Centre d'Ingénierie des Protéines, B6 Sart Tilman, Université de Liège, Belgium.
authors.forename: Cédric
authors.initials: C
authors.lastname: Bauvois
authors.forename: Akiko Shimizu
authors.initials: AS
authors.lastname: Ibuka
authors.forename: Almeida
authors.initials: A
authors.lastname: Celso
authors.forename: Jimena
authors.initials: J
authors.lastname: Alba
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ishii
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Frère
authors.forename: Moreno
authors.initials: M
authors.lastname: Galleni
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D007700:Kinetics; D010957:Plasmids / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases