An ENZYME produced by certain streptococci (see STREPTOCOCCUS). It acts as a PLASMINOGEN activator, and hence enhances FIBRINOLYSIS. The most important use of streptokinase is in the treatment of myocardial infarction (see HEART, DISEASES OF) in the first 12 hours after the initial diagnosis. Subsequently, use of this thrombolytic drug should be under hospital supervision. It is given intravenously, in hospital by infusion. It may be given as an infusion to treat severe THROMBOSIS or EMBOLISM, particularly when they occur in a limb, and in deep venous thrombosis.