STUDIES ON A PROTEOLYTIC ENZYME IN HUMAN PLASMA. IX. FIBRINOGEN AND FIBRIN AS SUBSTRATES FOR THE PROTEOLYTIC ENZYME OF PLASMA 1

Abstract

No appreciable difference was observed between the time required for the liquefaction of fibrin and for rendering fibrinogen incoagulable by active bovine or human plasma proteolytic enzyme (plasmin; fibrinolysin). This result agrees with the observation of Christensen that this enzyme digests fibrinogen and fibrin with equal avidity. When streptokinase was mixed with oxalated or native human plasma, it took a shorter time for fibrin to be dissolved than for fibrinogen to become incoagulable, as reported by Fantl et al. In the plasma of some patients with cirrhosis, "spontaneous" fibrinolysis occurred more rapldly than fibrino-genolysis. In the plasma of most normal individuals, and of other patients with cirrhosis, no difference was noted in the time required for the liquefaction of fibrin and digestion of fibrinogen. These expts. suggest that the activation of plasma proteolytic enzyme either spontaneously or by streptokinase, may be accelerated by the process of coagulation.