Clot uptake of labeled active and inhibited tissue plasminogen activator.
Biochim Biophys Acta
; 991(1): 62-7, 1989 Apr 25.
Article
em En
| MEDLINE
| ID: mdl-2496763
ABSTRACT
The clot uptake of labeled active and inhibited t-PA was compared. The most efficient inhibition was obtained with diisopropyl fluorophosphate (DFP) after 4 h incubation at room temperature. Enzyme activity was followed by fibrin-plate assay, radioactivity-release technique and proton magnetic resonance (PMR). The novel PMR method developed by us is sensitive to the effect of as low as nanogram amounts of t-PA on the interaction between the fibrin and the compartmentalized water trapped in the clot. Binding of labeled enzyme to fibrin-coated plates showed that the deactivation by DFP did not impair the affinity of t-PA for fibrin. A rapid binding of 125I-labeled t-PA to the clot occurred, which reached a maximum in 30 min and declined with time. This pattern was explained by consecutive clot binding and lysis. The binding of DFP-t-PA to the clot differed markedly from that of the active protein; 2 h post-incubation the uptake of DFP-t-PA was more than double that of the untreated t-PA. Parallel measurements in clots prepared from human blood showed a qualitatively similar trend. The biodistribution of radiolabeled t-PA in mice was similar for the active and inhibited forms. Blood activity reached 10% of the injected dose within 10 min. DFP-t-PA may prove to be a useful reagent for in-vivo localization of thrombi.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Coagulação Sanguínea
/
Fibrina
/
Ativador de Plasminogênio Tecidual
Limite:
Animals
/
Female
/
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
Israel