Synthesis of alpha-tocopherolquinone by the rat and its reduction by mitochondria.
The combination of alpha-tocopherolquinone and alpha-tocopherolquinol varied in tissues of the rat from 20 nmol/g of adipose tissue to 215 nmol/g of liver. In each tissue except the brain, the alpha-tocopherolquinone and alpha-tocopherolquinol were about equal. In the brain, the level of the hydroquinone was more than 5 times the level of the quinone. Neither compound was detected in blood. Both [2-14C5mevalonic acid and L-[14C]tyrosine were incorporated into alpha-tocopherolquinone but not into alpha-tocopherol. This indicates that alpha-tocopherol is not the precursor of alpha-tocopherolquinone. In the presence of beta-hydroxybutyrate, pyruvate, succinate, and NADH, alpha-tocopherolquinone was reduced to alpha-tocopherolquinol by liver mitochondria. Since the reduction was not inhibited by rotenone or antimycin A, it is likely that the reduction of alpha-tocopherolquinone is not part of the classical mitochondrial electron transport system.
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008798:Mevalonic Acid / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D013154:Spleen / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism
D014810:Vitamin E; D014443:Tyrosine; C002421:tocopherylquinone; D008798:Mevalonic Acid