The action of -lactamases on desacetyl-cefotaxime and cefotaxime

Publisher Website
Google Scholar
Abstract
Desacetyl-cefotaxime is the main cefotaxime metabolite. Its antibacterial activity is less than that of the parent molecule, but the combination of cefotaxime and desacetyl-cefotaxime is often synergistic. We analysed the hydrolysis of desacetylcefotaxime, in comparison with cefotaxime, by 10 β -lactamases, mostly cephalosporinases, isolated from various Gram-negative species. From partially purified β -lactamase preparations of high specific activity, we determined the maximum rates of hydrolysis ( V m ) and the Michaelis constants ( K 1 and K m when possible). It appeared for 7 β -lactamases the rate of desacetyl-cefotaxime hydrolysis was 2.1 times greater than that of cefotaxime, in terms of geometrical mean value, but with 3 enzymes no hydrolysis was shown for one compound. For 8 enzymes, the K 1 , and sometimes K m , of desacetyl cefotaxime are 39 times higher than those of cefotaxime (geometric mean value), which corresponds to a lower affinity.

This publication has 0 references indexed in Scilit: