A Functional Transsulfuration Pathway in the Brain Links to Glutathione Homeostasis* Journal of Biological Chemistry 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 redox cycle. Glutathione (GSH) is synthesized from the Download Scientific Diagram Peptides for Longevity: BPC 157, TB 500, GHK Cu & CJC 1295 GLOW GHK Cu TB 500 BPC 157 Research Blend 70mg Tissue Repair Peptide NeuroPept Labs Glutamyl Cycle