Plasminogen activator in bladder tumors.

Plasminogen activator was recovered from bladder tumors by 30% ammonium sulfate precipitation, acid treatment and concanavalin A-Sepharose affinity chromatography to a purification factor of about 80,000. The pooled fraction from the binding protein to concanavalin A-Sepharose revealed a single enzymatically active band with molecular weight of 55,000, which lost its enzymatic activity in the absence of plasminogen. The enzymatic activity was inactivated by DFP. The purified plasminogen activator reacted with antibody against UK, and not with that against t-PA. The purified plasminogen activator cleaved S-228 to a greater extent than S-2444, although UK cleaved S-2444 to a greater extent that S-2288. The enzymatic activity was strongly inhibited by basic pancreatic trypsin inhibitor, and benzamidine. These results suggest that the plasminogen activator in bladder tumors may belong to a different category of plasminogen activator.