On the involvement of intramolecular protein disulfide in the irreversible inactivation of 3-hydroxy-3-methylglutaryl-CoA reductase by diallyl disulfide

Omkumar, RV and Kadam, SM and Banerji, A and Ramasarma, T (1993) On the involvement of intramolecular protein disulfide in the irreversible inactivation of 3-hydroxy-3-methylglutaryl-CoA reductase by diallyl disulfide. In: Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1164 (1). pp. 108-112.

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Abstract

Treatment with diallyl disulfide, a constituent of garlic oil, irreversibly inactivated microsomal and a soluble 50 kDa form of HMG-CoA reductase. No radioactivity was found to be protein-bound on treating the soluble enzyme with [35S]diallyl disulfide, indicating the absence of the mixed disulfide of the type allyl-S-S-protein. SDS-PAGE and Western blot analyses of the diallyl-disulfide-treated protein showed no traces of the dimer of the type protein-S-S-protein, but clearly indicated BME-reversible increased mobility, as expected of an intramolecular protein disulfide. The sulfhydryl groups, as measured by alkylation with iodo[2-14C]acetic acid, were found to decrease in the diallyl-disulfide-treated enzyme protein. Tryptic peptide analysis also gave support for the possible presence of disulfide-containing peptides in such a protein. It appears that diallyl disulfide inactivated HMG-CoA reductase by forming an internal protein disulfide that became inaccessible for reduction by DTT, and thereby retaining the inactive state of the enzyme.

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	HMG-CoA reductase;Diallyl disulfide;Enzyme inactivation; Irreversible inactivation;Intramolecular disulfide.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	18 Feb 2011 08:26
Last Modified:	18 Feb 2011 08:26
URI:	http://eprints.iisc.ac.in/id/eprint/35648

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