The studies of activation mechanism of fibrinolysis using by chromogenic substrates

The activation mechanism of human plasminogen by SK and/or UK were studied using chromogenic substrates. When plasminogen was activated by small doses of SK, plasmin generation was slowly as well as UK-activation and reached maximum at about 10min, after mixing of two materials. But in the case of activation by high doses of SK, both activities of plasmin (S-2251) and plasminogen activator (S-2444) showed highest immediately because of formation of plasmin-SK complex.Plasmin-SK complex had not only activity of plasmin but also activity of plasminogen activator and Km of that for S-2251 was 1.74×10-3mol/l compared with plasmin: 8.6×10-4mol/l, Vm of plasmin-SK complex: 2941, plasmin: 714, respectively.