Methionine, cysteine and branched chain amino acids PPT How Glutathione Works: Detoxification Cycle Explained Mandy L. posted on the topic LinkedIn 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 Glutathione Metabolism in Plants under Stress: Beyond Reactive Oxygen Species Detoxification The ascorbateglutathione cycle coming of age