Selenium, antioxidants, cardiovascular disease, and all cause mortality: a systematic review and meta analysis of randomized controlled trials The American Journal of Clinical Nutrition Glutathione peroxidase hi res stock photography and images Alamy Glutathione: The Master Antioxidant Core Med Science TJ. Glutathione peroxidase is an important enzyme in cellular antioxidant defense systems, detoxifying peroxides and hydroperoxides. As a component of the glutathione cycle, it protects the liver from reactive oxygen metabolites. Selenocysteine Protection Against Oxidative Stress and IGF I Deficiency Conditions IntechOpen Assay for quantitative determination of glutathione and glutathione disulfide levels using enzymatic recycling method Nature Protocols