title: Fish plasminogen activators: their identification and characterization.
abstract: Immunoblots of proteins extracted from the skin of a small viviparous fish (Xiphophorus) showed that a monoclonal antibody against human urokinase recognizes multiple molecular weight species of antigens. The immunoaffinity-purified antigens had serine-protease activity for the hydrolysis of a chromogenic substrate and could convert human plasminogen to plasmin in a manner similar to that for human urokinase in vitro. Two antigens with apparent molecular weights of 55 and 50 kilodaltons that had been purified on a fibrin-Celite column were separable on SDS-polyacrylamide gels and were characterized as major plasminogen activators on fibrin-agar indicator plates. The 125I-tryptic peptide maps of both antigens were similar to that of human urokinase; therefore, the fish activators and human urokinase are structurally and functionally related.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003532:Cyprinodontiformes / Q000502:physiology*; D007163:Immunosorbent Techniques; D007700:Kinetics; D008547:Melanophores / Q000201:enzymology; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010958:Plasminogen / Q000378:metabolism; D010960:Plasminogen Activators / Q000302:isolation & purification* / Q000378:metabolism; D014357:Trypsin; D014568:Urokinase-Type Plasminogen Activator / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D010958:Plasminogen; D010960:Plasminogen Activators; D014357:Trypsin; D014568:Urokinase-Type Plasminogen Activator