The Fibrinolytic Activity of Streptokinase Activated Human Plasmin 1

The Mechanism of Clot Dissolution by Plasmin*

“…It is evident that the two distinct activities of plasminogen preparations developed under the influence of streptokinase, the proteolytic and the activator activities, are differently related to the streptokinase concentrations employed. Whereas, proteolytic activity reaches a plateau at 100 streptokinase units per ml., which is maintained with 9 There is still controversy as to whether proactivator is an entirely separate substance or is derived from plasminogen itself (22,23,24), but the term is used to designate a plasma factor capable of reacting with streptokinase to form plasminogen activator. Though divergent emphasis has been placed on the significance of proactivator in the human as apart from the bovine system (25,26,27) for descriptive purposes we acknowledge its separate existence and assay for its biochemical activity even though its individual identity apart from plasminogen or its derivatives has not been clearly established.…”

Pathogenesis of the Coagulation Defect Developing During Pathological Plasma Proteolytic (“Fibrinolytic”) States. I. The Significance of Fibrinogen Proteolysis and Circulating Fibrinogen Breakdown Products*

“…Consequently, the release of both thromboplastic material and plasminogen activator might notably increase the severity of the coagulation defect through the rapid lysis of intravascular fibrin deposits. Such a combined release of thromboplastic material and plasminogen activator would be expected to produce particularly severe coagulation anomalies, of the type observed clinically in obstetric patients, 912 since the rate of lysis of fibrin deposited in the presence of plasminogen activators greatly exceeds that of fibrinogenolysis (19,20,71,72).…”

Studies of the Plasmin System

“…Fibrin digestion is the favorite method for determination of plasmin and dots for this purpose are commonly formed from animal fibrinogen that is only partially purified. A number of workers have shown that these dots are contaminated with plasminogen from their animal source (20,31). Consequently, lysis may be induced not only by the plasmin of the sample under test, but also by plasmin activated from the dot.…”