Summary
Samples of an activation mixture, consisting of fibrinogen, streptokinase and plasma
(source of pro-activator) were added to thrombin at intervals of 1 minute and subjected
to lysis time determinations; the absence of clotting was noted after a certain period
of incubation. At this point, the lysis time was no longer measurable.
Inhibition of coagulation was not observed if either bovine fibrinogen or human plasma
were incubated with streptokinase alone. If, however, human fibrinogen was used instead
of bovine fibrinogen, this effect occurred even if only fibrinogen and streptokinase
were incubated.
The mechanism of the process described was investigated by varying the different streptokinase-
and fibrinogen concentrations, using either undiluted or diluted plasma.
It was evident that there is a relationship between the concentrations of fibrinogen
and streptokinase on the one hand, and the degree of plasma dilution on the other.
Fibrinogenolysis is caused by activation of the pro-enzyme contained in the fibrinogen
preparations. During this process, fibrinogen is altered to a non-coagulable protein.
