THE INHIBITION OF BLOOD CLOTTING: AN UNIDENTIFIED SUBSTANCE WHICH ACTS IN CONJUNCTION WITH HEPARIN TO PREVENT THE CONVERSION OF PROTHROMBIN INTO THROMBIN

Abstract

The effect of heparin in blocking the conversion of prothrombin into thrombin requires the presence of plasma of an accessory inhibitory factor not previously recognized. Heparin alone does not block the formation of thrombin and the new factor alone has very little inhibitory power. However, the 2 together are highly effective in doing so. The new plasma factor is shown to be non-dialyzable but its identity is not yet established.