Structure-activity relationships in the inhibition of serine beta-lactamases by phosphonic acid derivatives.
A new series of phosphonyl derivatives has been prepared and tested for inhibition of serine (classes A and C) beta-lactamases. The results were compared with those previously acquired with aryl phosphonate monoesters and with alkaline hydrolysis rates. A methyl p-nitrophenyl phosphate monoanion was markedly poorer as an inhibitor of the class C beta-lactamase of Enterobacter cloacae P99 than a comparable p-nitrophenyl phosphonate. Phosphonyl fluorides, thiophenyl esters, N-phenylphosphonamidates and a p-nitrophenyl thionophosphonate were, in general, comparable with p-nitrophenyl phosphonates in inhibitory power. The incorporation of a specific amino side chain led to an increase in the rates of inhibition of around 10(4)-fold. Apparently unresponsive to the addition of the side chain to the enzyme was N-phenyl methylphosphonamidate, where binding of the side chain may interfere with access of the leaving group to a proton which is necessary to active-site phosphonylation and inhibition. Typical class A beta-lactamases were significantly more refractory than the class C enzyme to all of these reagents.
Rahil
J
J
Department of Chemistry, Wesleyan University, Middletown, CT 06459.
Pratt
R F
RF
D016972:Enterobacter cloacae / Q000201:enzymology; D007202:Indicators and Reagents; D007700:Kinetics; D063065:Organophosphonates / Q000138:chemical synthesis / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000145:classification
D007202:Indicators and Reagents; D063065:Organophosphonates; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases