Glutathione peroxidase Stock Vector Images Alamy SciELO Brasil Oxidative stress: molecular perception and transduction of signals triggering antioxidant gene defenses Oxidative stress: molecular perception and transduction of signals triggering antioxidant gene defenses 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 Natural Small Molecules Targeting Oxidative Stress and Redox Homeostasis in Aging: Mechanisms and Therapeutic Potential