Covalent binding of moxalactam to cephalosporinase of Citrobacter freundii.
AUTOR(ES)
Murakami, K
RESUMO
The inhibition of Citrobacter freundii cephalosporinase activity by moxalactam is shown to be due to the formation of a transiently stable covalent complex, probably acyl enzyme. The covalent complex formed was identified by coelution of [14C] moxalactam with the enzyme by using Sephadex G-25 gel filtration in the presence of 5.7 M guanidine hydrochloride and by analytical isoelectric focusing. Both the side-chain carboxyl group and the 7 alpha-methoxy group of moxalactam were necessary to stabilize the complex. Moxalactam is racemic with respect to the alpha carbon of the 7 beta-acylamino side chain, and the complex with the R epimer (half-life, 4.6 min) decomposed much more rapidly than that formed with the S epimer (half-life, 130 min). For other beta-lactam antibiotics that were stable to beta-lactamase, the half-lives of enzyme-antibiotic complexes were less than 4 min.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=180142Documentos Relacionados
- Carbapenem resistance in a clinical isolate of Citrobacter freundii.
- DNA sequence differences of ampD mutants of Citrobacter freundii.
- Purification and characterization of selenocysteine beta-lyase from Citrobacter freundii.
- Nucleotide sequence for the htpR gene from Citrobacter freundii.
- Kinetic studies on inactivation of Citrobacter freundii cephalosporinase by sulbactam.