Selenium Status and Glutathione Metabolism
Selenium, vitamin E, and sulfur amino acids have long been considered to serve as antioxidants that complement one another. Selenium is an essential component of intracellular and extracellular glutathione peroxidases. (See chapters 3 and 4.) Vitamin E is a membrane-associated molecule that scavenges free radicals, preventing damage to membrane lipids (Witting, 1980). Glutathione (GSH) reacts with free radicals nonenzymatically and is also a substrate for many enzyme systems. The central role of glutathione in oxidant defense has recently been strengthened by discoveries showing that it regenerates vitamin E and ascorbic acid from free radical metabolites of them (Meister, 1992). Deficiencies of selenium, vitamin E, and/or GSH often result in increased sensitivity to oxidant stress. The relationships of glutathione with the antioxidant nutrients are important. Figure 8.1 depicts the formation and fate of cellular GSH. Elements of the scheme that are affected by selenium deficiency are highlighted. The relationship between selenium and glutathione will be discussed in this chapter.
KeywordsGlutathione Peroxidase Glutathione Peroxidase Activity Selenium Deficiency Glutathione Metabolism Cumene Hydroperoxide
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