Thioredoxin reductase reduces lipid hydroperoxides and spares alpha-tocopherol.
We investigated whether and how rat liver thioredoxin reductase spares alpha-tocopherol in biomembranes. Purified hydroperoxides of beta-linoleoyl-gamma-palmitoylphosphatidylcholine were decreased 35% by treatment with thioredoxin reductase and 54% by thioredoxin reductase plus E. coli thioredoxin. Thioredoxin reductase also halved the amount of hydroperoxides that had been formed during photoperoxidation of liposomes composed of beta-linoleoyl-gamma-palmitoylphosphatidylcholine, and of emulsions of both cholesterol and cholesteryl linolenate. In erythrocyte ghosts, thioredoxin reductase spared alpha-tocopherol from oxidation by both soybean lipoxygenase and ferricyanide. Thioredoxin reductase also decreased F(2)-isoprostanes in ghosts oxidized by ferricyanide, suggesting that its ability to spare alpha-tocopherol relates to reduction of lipid hydroperoxides.
May
James M
JM
Department of Medicine, Vanderbilt University School of Medicine, 715 Preston Research Building II, 2220 Pierce Avenue, Nashville, TN 37232-6303, USA. james.may@mcmail.vanderbilt.edu
Morrow
Jason D
JD
Burk
Raymond F
RF
D000818:Animals; D004910:Erythrocyte Membrane / Q000378:metabolism; D005292:Ferricyanides / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000378:metabolism*; D008084:Lipoxygenase / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D051381:Rats; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism*; D024502:alpha-Tocopherol / Q000378:metabolism*
D005292:Ferricyanides; D008054:Lipid Peroxides; C007931:hexacyanoferrate III; D008084:Lipoxygenase; D013880:Thioredoxin-Disulfide Reductase; D024502:alpha-Tocopherol