Calpastatin simultaneously binds four calpains with different kinetic constants.
FEBS Lett
; 581(16): 2894-8, 2007 Jun 26.
Article
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| MEDLINE
| ID: mdl-17543955
ABSTRACT
Calpastatin is the endogenous, specific protein inhibitor of the calcium-dependent protease, calpain. Using an active site knock-out m-calpain mutant we have studied the enzyme's calcium-dependent binding to calpastatin by surface plasmon resonance without the complication of proteolysis. Calpastatin was capable of simultaneously binding four molecules of calpain. Its four inhibitory domains (CAST1, 2, 3, and 4) were individually expressed in Escherichia coli and the kinetics of their interaction with calpain was separately compared. Their K(d) values ranged from picomolar to nanomolar in the order CAST1>4>3>2. They have similar k(on) values but the k(off) values ranged over three orders of magnitude and can account for the differences in affinity.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Proteínas de Unión al Calcio
/
Calpaína
Límite:
Animals
Idioma:
En
Revista:
FEBS Lett
Año:
2007
Tipo del documento:
Article
País de afiliación:
Canadá