beta-Lactamase K1 from Klebsiella aerogenes 1082E hydrolyses both penicillins and cephalosporins comparably and is inhibited by mercurials but not by cloxacillin. These properties distinguish it from those other beta-lactamases that have been allotted to classes on the basis of their amino sequences. beta-Lactamase K1 has been isolated by affinity chromatography; its composition shows resemblances to class A beta-lactamases. Moreover, the N-terminal sequence is similar to those of class A beta-lactamases: there is about 30% identity over the first 32 residues. Furthermore, a putative active-site octapeptide has been isolated and its sequence is similar to the region around the active-site serine residue in class A beta-lactamases. There is one thiol group in beta-lactamase K1; it is not essential for activity. The pH-dependence of kcat. and kcat./Km for the hydrolysis of benzylpenicillin by beta-lactamase K1 were closely similar, suggesting that the rate-determining step is cleavage of the beta-lactam ring.
Research Article| March 01 1986
Structural and kinetic studies on β-lactamase K1 from Klebsiella aerogenes
Biochem J (1986) 234 (2): 343–347.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
E L Emanuel, J Gagnon, S G Waley; Structural and kinetic studies on β-lactamase K1 from Klebsiella aerogenes. Biochem J 1 March 1986; 234 (2): 343–347. doi: https://doi.org/10.1042/bj2340343
Download citation file: