Biological and thrombolytic properties of proenzyme and active forms of human urokinase. I. Fibrinolytic and fibrinogenolytic properties in human plasma in vitro of urokinases obtained from human urine or by recombinant DNA technology
Thrombosis and haemostasis vol:52 issue:1 pages:19-23
The fibrinolytic and fibrinogenolytic properties of recombinant pro-urokinase (Rec-pro-UK) and recombinant urokinase (Rec-UK) obtained by expression of the human urokinase cDNA in E. coli, were compared with those of natural urokinase (Nat-UK) of urinary origin and of tissue-type plasminogen activator (t-PA) in a system, composed of a radioactive human plasma clot immersed in citrated human plasma. The specific fibrinolytic effects of Nat-UK, Rec-pro-UK and Rec-UK were very similar, causing significant clot lysis at concentrations of 100 IU/ml plasma or more. t-PA caused equivalent degrees of clot lysis at 10-fold lower concentrations. Activation of the fibrinolytic system in the plasma (fibrinogenolysis), was not observed with t-PA in concentrations which induced complete clot lysis within 5 hr (20-30 IU/ml plasma). With Nat-UK and Rec-UK, all concentrations which caused significant clot lysis (100-200 IU/ml plasma) also caused extensive activation of the plasma fibrinolytic system. With Rec-pro-UK an intermediate response was obtained. The highest amounts required for complete clot lysis in 5 hr (200 IU/ml plasma) also caused significant fibrinogenolysis. At intermediate concentrations (50-100 IU/ml), however, significant clot lysis (40-80%) was observed without systemic fibrinolytic activation.