title: Cryptic and active plasminogen activators secreted by line 10 tumor cells in culture.
abstract: Line 10 guinea pig carcinoma cells cultured in serum-free medium for 4 hr elaborate plasminogen activator (PA) activity that remained in the supernatant after ultracentrifugation (100,000 X g, 90 min). PA activity in line 10 conditioned medium occurred in both active and cryptic forms. The vast majority of active PA adsorbed to lysine-Sepharose and could be eluted at low pH as several activities that electrophoresed in the Mr 50,000 to 80,000 range on nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A small amount of active PA, running in the Mr 50,000 to 60,000 region, and cryptic PA did not adhere to lysine-Sepharose. Treatment of lysine-Sepharose-nonadherent fractions with catalytic amounts of plasmin or trypsin induced substantial new PA activity that adsorbed to lysine-Sepharose, bound [3H]diisopropylfluorophosphate, and that electrophoresed as several bands of activity with molecular weights from 50,000 to greater than 100,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Of additional interest, the amount of active PA measured in conditioned medium was substantially increased when certain protease inhibitors, tranexamic acid, epsilon-aminocaproic acid, or Trasylol, were included during culture.
mesh_terms: D000818:Animals; D001650:Bile Duct Neoplasms / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005337:Fibrin / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008970:Molecular Weight; D009374:Neoplasms, Experimental / Q000378:metabolism; D010960:Plasminogen Activators / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005337:Fibrin; D010960:Plasminogen Activators