Vitamin E protects proteins against free radical damage in lipid environments.
The fragmentation of the membrane protein monoamine oxidase in submitochondrial particles was induced by defined free radicals during radiolysis and by a system dependent on hydrogen peroxide and a transition metal. By injection of alpha-tocopherol in vivo, the levels of this physiological antioxidant in the mitochondrial preparations could be elevated more than ten-fold. In both radical-generating systems the presence of high levels of alpha-tocopherol in the membrane substantially retarded the protein fragmentation, in parallel with lipid peroxidation. It is suggested that membrane-bound proteins are damaged during lipid peroxidation and that alpha-tocopherol protects cells against both types of damage.
Cell Biology Research Group, Brunel University, Uxbridge, Middlesex, U.K.
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Dean
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Cheeseman
D000818:Animals; D005609:Free Radicals; D006861:Hydrogen Peroxide; D066298:In Vitro Techniques; D008054:Lipid Peroxides; D008297:Male; D008670:Metals; D008995:Monoamine Oxidase; D051381:Rats; D013367:Submitochondrial Particles / Q000201:enzymology; D014810:Vitamin E
D005609:Free Radicals; D008054:Lipid Peroxides; D008670:Metals; D014810:Vitamin E; D006861:Hydrogen Peroxide; D008995:Monoamine Oxidase