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

Abstract

Summary

Aqueous solutions of purified prothrombin, stored in a freezer at —10°C, lose appreciable activity over a period of a few weeks. Concomitantly, these solutions 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 solutions as the prothrombin substrate. It is believed that prothrombin itself becomes modified and acquires accelerator properties. The possibility of an impurity acquiring these propertiesis not excluded, although that Is considered unlikely.