AbstractAn established cell line (OC‐1) was obtained from human ovarian tissue, which yielded a high concentration of plasminogen activator (PA) in the culture medium. The PA (OC‐1‐PA) produced by the cell line was purified and compared with urokinase (UK), proform of UK (pro‐UK), and tissue‐type PA (t‐PA) purified from human melanoma cells (Bowes). OC‐1‐PA was purified by Zn chelate‐Sepharose affinity chromatography followed by high‐performance liquid chromatography with a Zn chelate‐5PW column and with a p‐amino‐benzamidine‐5PW column, giving a yield of 58.3% and a purification factor of 15,439. This purified material revealed a single band of Mr 55,000 on sodium dodecylsulfate polyacrylamide gel electrophoresis in the presence or absence of reducing agents. Electrophoresis enzymography demonstrated that the Mr 55,000 protein band had a plasminogen‐dependent fibrinolytic activity. Treatment with plasmin did not change the Mr even in the presence of reducing agents. These results suggest that OC‐1‐PA has a single‐chain structure protected from protease degradation, which is completely different from UK. The activator had higher affinities for lysine and fibrin than those of UK or pro‐UK. An immunological study demonstrated that OC‐1‐PA cross reacted with anti‐UK lgG but not with anti‐t‐PA lgG. All these findings indicate that OC‐1‐PA belongs immunologically to the
展开▼
