title: Differences in the activation rates of plasminogen by tissue plasminogen activator and urokinase.
abstract: The activation of a native form of plasminogen (Glu-plg) by tissue plasminogen activator(t-PA) was enhanced when the plasma was clotted by the addition of thrombin or thrombin plus Ca++. Cross-linking of fibrin in the clotted plasma did not inhibit the fibrin-associated enhancement of the activation of plasminogen by t-PA. When fibrinolysis induced by t-PA in the clotted plasma was measured using enzyme immunoassay, lysis of non cross-linked fibrin in the clotted plasma was faster than lysis of cross-linked fibrin, however such decrease in the extent of fibrinolysis was observed in cross-linked fibrin even in the absence of alpha 2antiplasmin (alpha 2AP) in a purified system. When Glu- or Lys-plg (modified plg) was activated by t-PA, the presence of fibrin enhanced significantly the extent of activation of both Glu- and Lys-plg, but the activation of Glu-plg by urokinase (UK) was enhanced in the presence of fibrin. The activation of Lys-plg by UK was rather inhibited in the presence of fibrin.
mesh_terms: D004789:Enzyme Activation / Q000187:drug effects; D005337:Fibrin / Q000378:metabolism / Q000502:physiology; D005340:Fibrinogen / Q000502:physiology; D005342:Fibrinolysis / Q000187:drug effects; D006801:Humans; D010446:Peptide Fragments / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D011487:Protein Conformation; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology*; D000979:alpha-2-Antiplasmin / Q000502:physiology
chemical_list: D010446:Peptide Fragments; D000979:alpha-2-Antiplasmin; C018998:lysyl-plasminogen; D005337:Fibrin; D005340:Fibrinogen; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator