Glutathione’s (GSH’s) main role as an antioxidant is the use of its thiol (-SH) group as a nucleophilic scavenger and electron donor. However, glutathione (GSH) has several other vital maintenance functions, including:
- A cofactor in the function of several antioxidant enzymes including, glutathione peroxidases, which are responsible for the degradation of peroxides and glutathione transferases which are responsible for the detoxification of xenobiotics.
- Maintenance of ascorbate (Vitamin C) in its reduced state so it can remain an effective antioxidant/reducing agent. It does this through the activity of the glutathione-dependent enzyme dehydroascorbate reductase.
- An essential component in an NADPH pathway that prevents cellular components from being oxidized. This function is essential for the maintenance of protein thiols, and the creation of deoxyribonucleotide precursors for DNA synthesis, through the reduction of ribonucleotides.
- Protein glutathionylation mediated through thiol disulfide exchange reactions which are involved in cellular signaling, cell-cycle regulation, proliferation and apoptosis.