Glutathione redox cycle. Glutathione (GSH) is synthesized from the Download Scientific Diagram Full article: Mimetics of the Selenoenzyme Glutathione Peroxidase: Novel Structures and Unusual Catalytic Mechanisms Pyroglutamic acidosis Deranged Physiology Ascorbate and Glutathione: The Heart of the Redox Hub1 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