Summary
Human serum plasminogen antiactivator was separated from serum antiplasmin by isoelectric precipitation and ammonium sulfate fractionation followed by Sephadex chromatography. With the use of human vascular activator it was demonstrated that the serum antiactivator is functionally distinct from serum antiplasmin. Both antiplasmin and antiactivator were irreversibly inactivated when incubated with synthetic fibrinolysis inducing compounds, this inactivation being independent from plasminogen activation. Minor structural modifications of the compounds which abolished the fibrinolytic activity also abolished their effects on serum antiactivator. It is suggested that the pathway of the compound-induced fibrinolysis is an unbalancing of the activator-antiactivator system by inactivating antiactivator, thus freeing the activator for plasminogen activation.
