The mechanism of inhibition of creatine kinase (CK) by acrylamide (Acr) has
been examined (in vitro). Within the concentration range of 0 to 1 M, Acr
markedly inhibited CK and depleted the protein thiols. Both inactivation an
d thiol depletion were time- and Acr concentration-dependent. Addition of d
ithiothreitol (DTT) did not reactivate CK inactivated by Acr. However, CK w
ith 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) pre-blocked thiols can be r
eactivated by DTT after incubation with Acr. The transition-state analogue
also had a significant protective effect on CK against Acr inhibition. We c
onclude that thiol alkylation is a critical event in inactivation of CK by
Acr. Furthermore, Acr binding to CK changed its surface charge, which may b
e the same effect for the toxicity of Aer towards other proteins. (C) 2001
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