New anticoagulant from lysed fibrinogen.

Abstract

SUMMARYOnce fibrinogenolysis had been initiated, few, if any fibrinogen molecules remained unaffected. Even the fraction which could still be precipitated by 0–25 per cent ammonium sulphate saturation showed differences from intact fibrinogen. Its solubility decreased very early, its coagulability gradually disappeared and the fraction itself acquired anticoagulant properties.The ability of the 0–25 per cent fraction to prolong the thrombin clotting time of intact fibrinogen varied with incubation in a way similar to that of the 25–50 per cent fraction (AFIF). It was, however, less potent and it disappeared after heating at 60° C. for 15 minutes. The two anticoagulant fractions could be differentiated by the electrophoretic and thermo‐stable protein patterns, the degree of precipitability by ether, the effect of alkaline pH buffers and the effect of fraction concentration on the inhibitory activity.The main electrophoretic component of the 0–25 per cent fraction, responsible for the bulk of the inhibitory effect at 100 per cent CP, had a slightly slower mobility and lower specific activity than the main component of the 25–50 per cent fraction.Purified thrombin liberated acid soluble protein fragments from the 0–25 per cent fraction equal to about 1.5 per cent of the total protein.