Protective Effect of Fibrinogen on Accelerator-Globulin

Abstract

When plasma was subjected to the action of chemical and physical agents which involved denaturation, adsorption, and precipitation phenomena, it was observed repeatedly that those agents which effected a reduction of Ac-globulin activity in un-defibrinated plasma, effected a decidedly greater reduction in defibrinated plasma. In 4 spp. of animals, it was noted that increased Ac-globulin activity occurred only when the fibrinogen was precipitated out of soln., either by freezing and subsequent thawing or by spontaneous precipitation. When fibrinogen was redissolved in the same plasma from which it was precipitated, Ac-globulin activity was reduced almost to that of fresh unfrozen plasma. There was a striking increase in Ac-globulin activity between thrombin defibrinated plasma and non-defibrinated plasma. Preliminary quantitative data suggest that there is probably an inverse relationship, within limits, between Ac-globulin activity and the amt. of fibrinogen in plasma. The data also provide a probable explanation for the conversion of an inactive pro-enzyme accelerator in plasma to an active accelerator in defibrinated plasma and in serum.