The Effect of Heparin on Components of the Human Fibrinolytic System

Abstract

It was demonstrated with human urokinase, human fibrinolytic euglobulins and human pyrogen plasma as enzyme source, and with bovine fibrin plates and human plasma plates as substrate, that high heparin concentrations inhibit fibrinolysis of preformed fibrin, in contrast to small ones which may enhance this phenomenon, provided albumin is present. No interference could be observed in the absence of plasma, serum or albumin fraction. Albumin or substances associated with the albumin fraction are required for interference of heparin with fibrinolysis. This interference probably takes place with the action of plasmin on fibrin.