Effects of fibrin on the enhanced activation of plasminogen by urokinase and tissue plasminogen activator: role of cross-link.
When human plasma was activated by urokinase (UK) in the presence of thrombin, thrombin plus Ca++, Ca++ or in their absence and the plasmin activity was measured by the hydrolysis of S-2251, plasmin activity was higher in the presence of cross-linked or non cross-linked plasma clot. The results of similar experiments utilizing plasma after severe exercise indicated that the hydrolysis of S-2251 by plasma containing tissue plasminogen activator (t-PA) was also higher in cross-linked or non cross-linked plasma clot. Fibrinolysis was faster in thrombin-induced plasma clot, but was later shown significantly in plasma clot induced by thrombin and Ca++, whereas practically no fibrinogenolysis was shown in plasma. When Glu-plasminogen (Glu-plg) was activated by UK in the presence of cross-linked or non cross-linked fibrin and alpha 2 antiplasmin (alpha 2AP), fibrinolysis was faster in cross-linked fibrin than non cross-linked fibrin in the presence of alpha 2AP. No fibrinogenolysis was shown either. Plasmin activity measured by the hydrolysis of S-2251 was also higher in cross-linked or non cross-linked fibrin than in fibrinogen in the presence of alpha 2AP. These results indicate that enhanced activation of Glu-plg by UK or t-PA in the presence of fibrin was a more significant event than the inactivation of plasmin in the plasma clot or purified clot by alpha 2AP cross-linked to fibrin.
Takada
A
A
Watahiki
Y
Y
Takada
Y
Y
D002118:Calcium / Q000494:pharmacology; D005337:Fibrin / Q000494:pharmacology*; D005340:Fibrinogen / Q000378:metabolism; D005342:Fibrinolysis; D006801:Humans; D006868:Hydrolysis; D009842:Oligopeptides / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology*
D009842:Oligopeptides; C018788:valyl-leucyl-lysine 4-nitroanilide; D005337:Fibrin; D005340:Fibrinogen; D010958:Plasminogen; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator; D002118:Calcium