Concentration of a Prothrombin Conversion Accelerator and Thrombin Precursor From Serum

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

The method described by Seegers for obtaining purified prothrombin from plasma has been used for isolating a protein fraction from serum. The yields are about 20% as much protein from serum as from plasma. The serum product is a potent accelerator for the conversion of purified prothrombin to thrombin. Although the serum product contained very little prothrombin, as measured by quantitative two-stage analysis, thrombin could be obtained from it by activation in 25% sodium citrate solution. It is believed that the accelerator isolated from serum is a derivative of prothrombin.