Used to dissolve (lyse) fibrin or blood clots in anterior chamber of eye and in acute massive pulmonary emboli. enzyme produced by kidney and obtained from human urine or kidney tissue cultures. lyophilized white powder, soluble in water. An activator of endogenous fibrinolytic system, which converts plasminogen to plasmin and degrades fibrinogen, fibrin clots and other plasma protein. Derived from human source, less antigenic than enzymes with similar actions like streptokinase.