INHIBITION AND ACTIVATION OF ADENYLOSUCCINIC SYNTHETASE BY 8-AZAGUANOSINE TRIPHOSPHATE

Abstract

8-Azaguanosine triphosphate can function in place of GTP in the reaction catalyzed by adenylosuccinic synthetase. The Michaelis constant and maximal velocity for the reaction obtained with the analogue are lower than those obtained with GTP. As a result, 8-azaGTP increases the reaction rate at low GTP concentrations and inhibits competitively at high GTP concentrations. It is suggested that this type of inhibition might be exploited in the development of chemo-therapeutic analogues specific for tissues containing high concentrations of a coenzyme or metabolite.