StructureActivity Correlation between Natural Glutathione Peroxidase (GPx) and Mimics: A Biomimetic Concept for the Design and Synthesis of More Efficient GPx Mimics Mugesh 2001 Chemistry A European Journal Wiley Online Library Modelling changes in glutathione homeostasis as a function of quinone redox metabolism Scientific Reports 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 Fig. 4.