[Theoretical bases of thrombolytic therapy].

Purified streptokinase has in vitro a double biochemical activity on plasminogen. At a low molecular ratio of streptokinase/plasminogen, mainly plasmin is generated. At an equimolar streptokinase-plasminogen ratio, mainly a complex streptokinase-plasmin is formed. This complex has a low proteolytic activity but has a high activator activity on plasminogen and maintains esterolytic properties. It is likely that the reactions occurring in vitro with purified reagents also occur in vivo, the situation being nevertheless more complex because of the presence of inhibitors such as antistreptokinase and antiplasmins.