Purified Platelet Cofactor I and Purified Autoprothrombin II in Thromboplastin Generation Test

SummaryPurified bovine platelet cofactor I substituted for adsorbed plasma in the thromboplastin generation test when Ac-globulin was also supplied. Only 70 gamma/ml were needed. Purified bovine autoprothrombin II substituted for serum in the test. Only 9 gamma were equivalent to serum. Platelet cofactor I thus takes the place of the antihemophilic factor and autoprothrombin II substitutes for PTC and Stuart-Prower factor. We regard the autoprothrombin II preparation used as a single component derived from prothrombin.