Proteolytic modification of staphylokinse.

There are three types of staphylokinase of different isoelectric points (6.7, 6.1 and 5.7). Staphylokinse of pI 6.7 was converted to that of pI 6.1 and then to that of pI 5.7 by the treatment with trypsin. Heterogeneity of staphylokinase might be the result of post-translational modification by proteolytic enzyme.