2-Deoxy-2-fluoro-D-glycosyl fluorides. A new class of specific mechanism-based glycosidase inhibitors

Abstract

Mechanism-based glycosidase inhibitors are of considerable use in studies of enzyme mechanism, in studies of glycoprotein processing, and possibly therapeutically in control of sugar uptake. This paper describes a new general approach to mechanism-based inactivation of glycosidases which involves trapping a covalent glycosyl enzyme intermediate. This is achieved by use of 2-deoxy-2-fluoro-D-glycosyl fluorides, for which the rate of hydrolysis of the fluoroglycosyl enzyme intermediate is extremely slow, resulting in accumulation of the intermediate. Eleven different glycosidases were tested with their corresponding 2-deoxy-2-fluoro-D-glycosyl fluorides. Eight of the eleven were inactivated, four of them according to pseudo first-order kinetics and four according to a more complex kinetic scheme. The specificity of these inhibitors was investigated by assaying for inhibition of one enzyme with four different 2-deoxy-2-fluoro-D-glycosyl fluorides. Large differences in inactivation rate were observed which paralleled previously observed substrate specificities.