Activation of Prothrombin

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

In the activation of a prothrombin solution, only part of the prothrombin becomes biothrombin, some becomes autoprothrombin I and some becomes autoprothrombin II. Thrombin-thrombin is also obtained, and perhaps other derivatives of prothrombin are formed. Prothrombin thus has multiple potentialities and these can be developed in diverse ways. Ac-globulin, calcium ions and platelet factor 3 can be used to obtain autoprothrombin I. Thrombin and Ac-globulin transforms prothrombin to autoprothrombin II, while platelet factor 3 or calcium ions tend to inhibit the transformation. Since calcium ions and platelet factor 3 also function as activators in one of the prothrombin to biothrombin reactions they are either activators or inhibitors of prothrombin activation depending upon the specified conditions.