Characterisaton of human plasma thiol proteinase inhibitors.
Indian J Biochem Biophys
;
1998 Dec; 35(6): 377-81
Artículo
en Inglés
| IMSEAR
| ID: sea-27269
ABSTRACT
Earlier, we had reported purification of three thiol proteinase inhibitors (TPI-1 of 70 kDa, TPI-3 of 195 kDa and TPI-4 of 497 kDa) from human plasma. In the present study we report that TPI-1 binds to papain in the stoichiometry ratio (E/I) of 11 while TPI-3 and TPI-4 bind in the ratio of 1.51 and 3.21 respectively. The K(m) for papain with BAPNA as substrate and Kcat/K(m) values for TPI-1, TPI-3 and TPI-4 were 2.7 x 10(-6) M, 0.84 nM/sec; 3.2 x 10(-6) M, 0.75 nM/sec; and 3.6 x 10(-6) M, 0.72 nM/sec respectively. The Ki values were found to be 1.48 nM for TPI-1, 0.133 nM for TPI-3 and 0.117 nM for TPI-4. The UV absorption and fluorescence emission spectra study suggest involvement of aromatic residues in the binding process. This study suggests that TPI-4 is the most potent inhibitor of thiol proteinases.
Texto completo:
Disponible
Índice:
IMSEAR (Asia Sudoriental)
Asunto principal:
Espectrometría de Fluorescencia
/
Benzoilarginina-Nitroanilida
/
Sitios de Unión
/
Humanos
/
Papaína
/
Inhibidores de Cisteína Proteinasa
/
Activación Enzimática
Idioma:
Inglés
Revista:
Indian J Biochem Biophys
Año:
1998
Tipo del documento:
Artículo
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