Format

Send to

Choose Destination
FEBS Lett. 2007 Jun 26;581(16):2894-8. Epub 2007 May 25.

Calpastatin simultaneously binds four calpains with different kinetic constants.

Author information

1
Department of Biochemistry, Queen's University, Kingston, Ontario, Canada. 9rah3@qlink.queensu.ca

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.

PMID:
17543955
DOI:
10.1016/j.febslet.2007.05.035
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center