[Regulation of cooperative properties of alpha-ketoglutarate dehydrogenase by means of thiol-disulfide metabolism].
The redox state of two SH-groups per enzyme subunit has been shown to control the cooperative properties of alpha-ketoglutarate dehydrogenase. These thiols oxidized, alpha-ketoglutarate dehydrogenase does not exhibit any cooperative properties. The enzyme reduction leads to subunit interactions. It has been found that the most effective agent reducing the alpha-ketoglutarate dehydrogenase thiols essential for the cooperativity is dihydrolipoate, one of the intermediates of the overall alpha-ketoglutarate dehydrogenase reaction. The possibility of changing the properties of alpha-ketoglutarate dehydrogenase in the multienzyme complex under the conditions when the lipoic acid integrated into the complex is reduced, has been investigated. Thus, incubation of the alpha-ketoglutarate dehydrogenase complex with NADH has been found to induce the conversion from the non-cooperative form to the cooperative one, presumably through the reduction of lipoic acid bound to the complex in the reaction catalyzed by lipoyl dehydrogenase, the third component of the complex.
Bunik
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Gomazkova
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D000818:Animals; D010856:Columbidae; D004220:Disulfides / Q000378:metabolism*; D007655:Ketoglutarate Dehydrogenase Complex / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D010084:Oxidation-Reduction; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D008063:Thioctic Acid / Q000031:analogs & derivatives / Q000378:metabolism
D004220:Disulfides; D013438:Sulfhydryl Compounds; D008063:Thioctic Acid; C015144:dihydrolipoic acid; D007655:Ketoglutarate Dehydrogenase Complex
Reguliatsiia kooperativnykh svoĭstv alpha-ketoglutaratdegidrogenazy petem tiol-disul'fidnogo obmena.