title: Purification of beta-lactamases and enzyme kinetic studies on aztreonam.
abstract: Standard beta-lactamases K1, P99, TEM-1, SHV-1 and beta-lactamase K-CAZ purified using FPLC through ion-exchange chromatography and filtration chromatography, were identified by determination of isoelectric points, molecular weights and substrate profiles. The results showed that the beta-lactamase stability of domestic aztreonam was very similar to that of cefotaxime, ceftazidime and much better than that of cefoperazone. Aztreonam showed a high affinity to chromosomal-mediated cephalosporinase P99, its Ki for inhibition of P99 with cephaloridine as substrate was 0.0159 microns. Aztreonam and the three third generation cephalosporins tested were not stable to beta-lactamase K-CAZ, which hydrolysed them in different degrees.
authors.affiliation: Institute of Clinical Pharmacology, Beijng Medical University.
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhao
authors.forename: J T
authors.initials: JT
authors.lastname: Li
mesh_terms: D001398:Aztreonam / Q000494:pharmacology*; D004795:Enzyme Stability / Q000187:drug effects; D004926:Escherichia coli / Q000201:enzymology; D006090:Gram-Negative Bacteria / Q000187:drug effects; D007700:Kinetics; D001618:beta-Lactamases / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D001618:beta-Lactamases; D001398:Aztreonam