[Thrombolytic action of urokinase preparation covalently bound to modified thrombin]

Urokinase was covalently bounded with modified thrombin. Thrombin was modified by carbodiimide and 1, 12-dodecamethylenediamine. In this conjugate thrombin is not catalytically active and does not induce platelets aggregation. The catalytic properties of modified urokinase do not essentially differ from native enzyme but its thermostability increases. The modified urokinase thrombolytic effect is at least 10-fold higher than the native one. In femoral arteries of experimental thrombosis the conjugate urokinase-thrombin brings about total thrombolytic effect as early as 1.5 hours after injection (2500 IU per 1 kg of the animals weight). The causes of the observed effect were discussed.