Studies on the Nature and the Purification of the Coagulase-reacting Factor and Its Relation to Prothrombin* by Morris

Although considerable progress has been achieved in the study of the coagulation of plasma by staphylocoagulase, the precise identity of the coagulase-reacting factor (CRF) has remained in doubt. The claims linking CRF with various factors involved in the dotting of blood have been recently summarized elsewhere (1). Questions pertaining to the possible relation of CRF to prothrombin have remained particularly challenging. To be sure, prothrombin and CRF activities have been dissociated by repeated Seitz (asbestos) filtration (2-4). While this observation establishes that CRF may exist independently of prothrombin activity, it does not preclude the possibility that other factors eliminated by the filtration procedure, including prothrombin itself, may function similarly. The prime objective of the present report has therefore been twofold: 1. To purify and characterize CRF as recovered from human plasma after prothrombin activity has been reduced to a minimum by serial Seitz filtration. 2. To study directly the CRF activity of highly purified preparations of human prothrombin.