Inhibition of one-chain and two-chain forms of human tissue-type plasminogen activator by the fast-acting inhibitor of plasminogen activator in vitro and in vivo
The inhibition of one-chain and two-chain molecular forms of human tissue-type plasminogen activator (t-PA) by the fast-acting inhibitor of plasminogen activator (PA-inhibitor) present in plasma was studied in vitro and in vivo in rabbits. In vitro, both one-chain and two-chain forms of t-PA were ne...
| Autores: | , , |
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| Formato: | artículo |
| Fecha de publicación: | 1986 |
| País: | España |
| Recursos: | Universidad de Navarra |
| Repositorio: | Dadun. Depósito Académico Digital de la Universidad de Navarra |
| Idioma: | inglés |
| OAI Identifier: | oai:dadun.unav.edu:10171/22923 |
| Acesso em linha: | https://hdl.handle.net/10171/22923 |
| Access Level: | acceso abierto |
| Palavra-chave: | Plasminogen Activators/antagonists & inhibitors Plasminogen Inactivators Tissue Plasminogen Activator/antagonists & inhibitors |
| Resumo: | The inhibition of one-chain and two-chain molecular forms of human tissue-type plasminogen activator (t-PA) by the fast-acting inhibitor of plasminogen activator (PA-inhibitor) present in plasma was studied in vitro and in vivo in rabbits. In vitro, both one-chain and two-chain forms of t-PA were neutralized very rapidly in rabbit plasma with high levels of PA-inhibitor. The rate constant of the interaction between two-chain t-PA and PA-inhibitor was estimated to be 3.10(7) L/mol/sec. The presence of CNBr-digested fibrinogen, which mimics the effect of fibrin on the activation of plasminogen by t-PA, did not influence the rate constant. Moreover, PA-inhibitor-rich plasma inhibited in a very similar way in vitro thrombolysis by one-chain or two-chain t-PA incorporated into the clot. Injection of one-chain or two-chain t-PA into rabbits with increased levels of PA-inhibitor, induced by endotoxin, resulted in very rapid inhibition of t-PA activity. Within 30 seconds after injection, no residual free t-PA could be demonstrated. Gel filtration analysis showed that the disappearance of t-PA activity was associated with the generation of t-PA-PA-inhibitor complex with an apparent Mr of 100,000. This enzyme-inhibitor complex, like free t-PA, was cleared from the circulation with a half-life of approximately 2 minutes, mainly via the liver. It is concluded that PA-inhibitor neutralizes one-chain and two-chain molecular forms of t-PA in plasma at very similar rates, both in vitro and in vivo.(ABSTRACT TRUNCATED AT 250 WORDS) |
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