RESUMO
The chromosome-encoded class C ß-lactamase CHE-1 produced by Enterobacter cloacae exhibits a lower sensitivity to avibactam than the P99 enzyme from which it is derived by a 6-residue deletion in the H-10 helix. In the present study, we investigated the sensitivity of CHE-1 to two other ß-lactamase inhibitors: LK-157 (or Lek 157), a tricyclic ß-lactam, and BAL29880, a bridged monobactam. With both compounds, the second-order rate constants for inactivation were significantly lower for CHE-1, which can thus be considered an inactivator-resistant mutant of P99. However, the second-order rate constant for the inactivation by BAL29880 probably remains adequate for a rather rapid reaction with CHE-1 in the absence of protection by the substrate.
Assuntos
Compostos Azabicíclicos/farmacologia , Carbapenêmicos/farmacologia , Enterobacter cloacae/efeitos dos fármacos , Monobactamas/farmacologia , Compostos de Fenilureia/farmacologia , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/genética , Enterobacter cloacae/enzimologia , Enterobacter cloacae/genética , beta-Lactamases/metabolismoRESUMO
Aminocitrate (and homolog) derivatives have been prepared by bis-alkylation of glycinate Schiff bases with bromoacetates (and ethyl acrylate), followed by N-acylation and esters (partial or complete) deprotection. Aminoisocitrate was similarly obtained by mono-alkylation with diethyl fumarate. Evaluation against representative beta-lactamases revealed that the free acid derivatives are modest inhibitors of class A enzymes, whilst their benzyl esters showed a good inhibition of OXA-10 (class D enzyme). A docking experiment featured hydrophobic interactions in the active site.