Prothrombin and Antithrombin: Their Opposing Functions in Blood Coagulation

Abstract

SummaryDuring the conversion of prothrombin to thrombin in plasma, continuous inactivation of thrombin by antithrombin occurs, and the accumulation of thrombin is dependent on the relative amounts of prothrombin and antithrombin. By selectively varying prothrombin and antithrombin concentrations, it is shown that the maximal thrombin concentration attained in plasma is directly proportional to the ratio of prothrombin to antithrombin, and that an increase in antithrombin is the practical equivalent of a decrease in prothrombin.