THE FIBRINOLYTIC-ACTIVITY OF STAPHYLOKINASE MUTANTS IN THE FIBRIN PLATE ASSAY

The fibrinolytic activity of the new plasminogen activator, recombinan t staphylokinase, was compared to that of streptokinase and tissue-typ e plasminogen activator in the fibrin The fibrinolytic activity of the new plasminogen activator, plate assay. The pattern of fibrinolysis b y staphylokinase on fibrin plates differs from the other plasminogen a ctivators. A number of mutants of staphylokinase with various amino ac ids in position 26 substituted for methionine in wild-type staphylokin ase were compared with respect to their fibrinolytic potencies. Only t he mutants with cysteine or leucine in this position have a fibrinolyt ic activity comparable to wild-type staphylokinase. The results on the fibrinolytic activities in the fibrin plate assay correlate with thos e of a plasmin generation assay, the latter is, however, less sensitiv e.