Prothrombokinase and the Three Stages of Blood Coagulation

Abstract

When plasma was diluted with distilled water and the pH brought to 5.0 to 5.5, the euglobulin ppt. contained the essential core of the clotting mechanism. The euglobulin prepn. clotted on addition of ionic Ca. The coagulation process involves 3 distinct stages: (1) prothrombokinase yielded thrombokinase (in the presence of Ca); (2) prothrombin yielded thrombin (in the presence of thrombokinase and Ca); (3) fibrinogen yielded fibrin (in the presence of thrombin). A method for studying the activation of prothrombokinase was descr. Previous lack of knowledge of such a method retarded the development of the newer concept of blood coagulation. The concn. of Ca was found to be important for the activation of prothrombokinase and also of prothrombin.