Nature of an Accelerator of Prothrombin Activation Arising During Storage of Purified Prothrombin.

Abstract

Aqueous solns. of purified prothrombin, stored in a freezer at -10[degree]C, lose appreciable activity in a few weeks. Concomitantly, these solns. gain the ability to accelerate the conversion of prothrombin to thrombin, as evidenced by an apparent increase in Ac-globulin activity of plasma analyzed by using the stored solns. as the prothrombin substrate. Apparently prothrombin itself becomes modified and acquires accelerator properties. The possibility of an impurity acquiring these properties is not excluded, although that is considered unlikely.