An Activated Intermediate Analogue

Abstract

Abstract At pH 7.5 and 25°, P-glycolohydroxamic acid is an effective inhibitor, competitive with dihydroxyacetone-P, of rabbit muscle triose-P isomerase (Ki = 4 µm) and yeast aldolase (Ki = 0.01 µm), enzymes which transiently form an enolate from dihydroxyacetone-P as part of their catalytic action. P-glycolohydroxamic acid is a poor inhibitor, again competitive with dihydroxyacetone-P, of rabbit muscle aldolase (Ki = 1,000 µm), which transiently forms a covalently bound enamine derivative of dihydroxyacetone-P as part of its catalytic action. It is argued that the first two enzymes are effectively inhibited by P-glycolohydroxamic acid because it can act as a stable analogue of the transiently occurring enolate derived from dihydroxyacetone-P.