Protein composition of plasmin preparation "homolysin"

A commercial preparation of human plasmin (Homolysin), capable of catalyzing the transformation of human growth hormone (hGH) into biologically activated species, was analyzed by electrophoresis and electrofocusing on polyacrylamide gel. Each major component of the preparation was characterized with regard to molecular size (retardation coefficient, KR), molecular net charge (y-intercept on the Ferguson plot, Y0), apparent isoelectric point (PI') and enzyme activity. The multiple components of Homolysin revealed by staining corresponded to various aggregation states of plasmin and exhibited full serine protease activity. Polyacrylamide gel electrophoresis of Homolysin in the presence of sodium dodecylsulfate (SDS) yielded 2 subunits which corresponded in molecular weight to the known plasmin subunits.