Inhibition of Autoprothrombin C Activity with Plasma

Abstract

THE traditional enzyme considered in the literature on blood coagulation is thrombin. It has its origin in prothrombin, which is a plasma protein isolated from bovine plasma and characterized in terms of physical chemical properties¹. When prothrombin activates, a stepwise degradation of the molecule occurs, and at least two of the intermediates, called autoprothrombin I and autoprothrombin II, can be involved in prothrombin activation². When the prothrombin is fully activated the activation mixture contains another accelerator which is different from autoprothrombin I or autoprothrombin II. This accelerator was only recently discovered and called autoprothrombin C because there was prothrombin consumption when it was added to hæmophilic plasma³. Autoprothrombin C has been separated from thrombin and is an enzyme⁴. A single molecule, prothrombin, is thus the source of two enzymes.