Acceleration of thrombin activity with Ac-globulin

¹ Department of Physiology and Pharmacology, Wayne State University College of Medicine, Detroit, Michigan

Purified Ac-globulin preparations accelerate the hydrolysis of p-toluenesulfonyl-l-arginine methyl ester (TAMe) by thrombin. Ac-globulin is the limiting factor in the reaction and does not itself hydrolyze TAMe. The increased thrombin activity is directly proportional to Ac-globulin concentration. More than a 25-fold increase in thrombin activity was obtained. The basic principle of accelerating TAMe hydrolysis with thrombin is tentatively proposed as a quantitative assay for Ac-globulin. A function of Ac-globulin in prothrombin activation is to increase the effectiveness of thrombin in the proteolytic degradation of the prothrombin substrate.