Studies on the prothrombin--complex

According to the theory of Seegers the clotting factors VII, IX, and X may generate from prothrombin during blood coagulation or purification procedures. For testing of this hypothesis prothrombin and the factors VII, IX and X were separated by BaSO₄ absorption and DEAE-cellulose column chromatography from blood with and without addition of protease inhibitors DFP or heparin-SBTI-benzamidine. The formation of thrombin and factors IXa and Xa was impeded by the inhibitors, whereas the factors II, VII, IX, and X were found in the same position whether inhibitors were present during the separation procedure or not. It is concluded that these factors exist in native blood as separate entities.