NADH-dependent decavanadate reductase, an alternative activity of NADP-specific isocitrate dehydrogenase protein

Rao, Aparna VS and Ramasarma, T (2000) NADH-dependent decavanadate reductase, an alternative activity of NADP-specific isocitrate dehydrogenase protein. In: Biochimica et Biophysica Acta(BBA), 1474 (3). pp. 321-330.

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Abstract

The well known NADP-specific isocitrate dehydrogenase (IDH) obtained from pig heart was found to oxidize NADH with accompanying consumption of oxygen $(NADH:O_2=1:1)$ in presence of polyvanadate. This activity of the soluble IDH-protein has the following features common with the previously described membrane-enzymes: heat-sensitive, active only with NADH but not NADPH, increased rates in acidic pH, dependence on concentrations of the enzyme, NADH, decavanadate and metavanadate (the two constituents of polyvanadate), and sensitivity to SOD and EDTA. Utilizing NADH as the electron source the IDH protein was able to reduce decavanadate but not metavanadate. This reduced form of vanadyl $(V^{IV})$ was similar in its eight-band electron spin resonance spectrum to vanadyl sulfate but had a 20-fold higher absorbance at its 700 nm peak. This decavanadate reductase activity of the protein was sensitive to heat and was not inhibited by SOD and EDTA. The IDH protein has the additional enzymic activity of NADH-dependent decavanadate reductase and is an example of ‘one protein-many functions’.

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta(BBA)
Publisher:	Elsevier
Additional Information:	Copyright of this artcle belongs to Elsevier.
Keywords:	Isocitrate dehydrogenase;NADH oxidation;Decavanadate reductase
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	03 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12045

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