STUDIES ON THE NATURE AND THE PURIFICATION OF THE COAGULASE-REACTING FACTOR AND ITS RELATION TO PROTHROMBIN

Abstract

By rigorous Seitz filtration and controlled phosphate buffer elution from celiteamphogel (aluminum hydroxide) columns, followed by ammonium sulfate fractionation, it was possible to obtain highly purified and concentrated preparation of human plasma globulin low in prothrombin activity but effective in reacting with staphylocoagulase in the clotting of fibrinogen. On the other hand, highly purified human prothrombin preparations of Seegers also function effectively as the coagulase-reacting factor (CRF). The ultracentrifugal and electrophoretic properties of the purified CRF and of human prothrombin are distinctive. The deliberate modification of purified prothrombin to either "autoprothrom-bin" or to thrombin, involving the elimination or very marked reduction of prothrombin activity does not correspondingly eliminate its capacity to react with coagulase. The parallelism of prothrombin and CRF activity, or its complete divergence, is best explained by assuming that some part of the prothrombin molecule may continue to function as CRF even though this component alone is not capable of acting as prothrombin.