A function for the vitamin E metabolite alpha-tocopherol quinone as an essential enzyme cofactor for the mitochondrial fatty acid desaturases.
A critical analysis of the changes in fatty acid patterns and their metabolism elicited by vitamin E deficiency leads to the proposal that a major role of dietary RRR-alpha-tocopherol (alpha-TOC) is as an enzymatic precursor of alpha-tocopherolquinone (alpha-TQ) whose semiquinone radical functions as an essential enzyme cofactor for the fatty acid desaturases of the recently elucidated carnitine-dependent, channeled, mitochondrial desaturation-elongation pathway; a detailed mechanism for its function is proposed. Pathophysiological states produced by vitamin E deficiency and alpha-TOC transfer protein defects, such as ataxia, myopathy, retinopathy, and sterility are proposed to develop from the effects of impaired alpha-TQ-dependent desaturases and the resulting deficiency of their polyenoic fatty acid products.
Infante
J P
JP
Institute for Theoretical Biochemistry and Molecular Biology, Ithaca, NY 14852-4512, USA. InstitTheorBiochem@netscape.net
D000818:Animals; D003067:Coenzymes / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000201:enzymology*; D013379:Substrate Specificity; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000378:metabolism
D003067:Coenzymes; D014810:Vitamin E; C002421:tocopherylquinone; D044943:Fatty Acid Desaturases