title: Purification and properties of an antiactivator fraction from bovine serum.
abstract: A method is described for the purification of antiactivator from bovine euglobulin-free serum by means of gelfiltration and ion exchange chromatography. The purified antiactivator has no antifibrinolytic activity. It has a molecular weight of about 115,000 and it appears to be a gamma globulin. The dissociation constant of its complex with urokinase is 1.6 x 10(-9) M and the maximum urokinase binding is close to 2000 CTA units per mg. Its concentration in bovine serum is 0.37%. Flufenamate displaces urokinase from the antiactivator at very low concentrations, about 10(-4) M. Cysteine restores its activity if lost by standing. Also an antifibrinolysin fraction is obtained free of antiactivator activity.
mesh_terms: D000818:Animals; D000933:Antifibrinolytic Agents / Q000494:pharmacology; D002417:Cattle; D005591:Chemical Fractionation; D011232:Chemical Precipitation; D002850:Chromatography, Gel; D003545:Cysteine / Q000494:pharmacology; D004588:Electrophoresis, Cellulose Acetate; D004591:Electrophoresis, Polyacrylamide Gel; D005439:Flufenamic Acid / Q000494:pharmacology; D006801:Humans; D008722:Methods; D008970:Molecular Weight; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors*; D015849:Plasminogen Inactivators; D012712:Serum Globulins; D014461:Ultracentrifugation; D005719:gamma-Globulins / Q000302:isolation & purification*
chemical_list: D000933:Antifibrinolytic Agents; D015849:Plasminogen Inactivators; D012712:Serum Globulins; D005719:gamma-Globulins; D005439:Flufenamic Acid; D010960:Plasminogen Activators; D003545:Cysteine