Glutathione (reduced)

Reduced glutathione (GSH) is a tripeptide, gamma-L-glutamyl-L-cysteinyl-glycine, with the molecular formula C10H17N3O6S and a molecular weight of 307.32. The unusual gamma-peptide bond between glutamate and cysteine gives it resistance to ordinary peptidases, and the cysteine thiol is the functional centre — GSH is the most abundant low-molecular-weight thiol in living cells and forms the GSH/GSSG redox couple that maintains cellular thiol balance and serves as the co-substrate for glutathione peroxidases and glutathione S-transferases. Thovek supplies USP-grade material assaying 98.0-101.0% on the dried basis by iodometric titration, with specific optical rotation of -15.5° to -17.5° (20 °C, 40 g/L in water, dried substance), loss on drying not more than 1.0% and heavy metals not more than 10 ppm. Commercial GSH is made by microbial fermentation rather than chemical synthesis, because fermentation reliably delivers the natural L-configuration without heavy-metal catalysts. Torula yeast (Candida utilis) and Saccharomyces cerevisiae are the standard production organisms; the yeast-fermented material is the subject of FDA GRAS Notice GRN 293, filed by Kohjin Co. Ltd. and closed with a no-questions letter on 22 December 2009 for use across baked goods, beverages, breakfast cereals and other food categories. Fermentation origin means non-GMO, vegan and non-animal declarations are straightforward, and Thovek supplies the strain and origin statement with each lot. GSH is hygroscopic and the thiol oxidises to the disulphide GSSG on exposure to air, moisture and warmth, so handling discipline matters more than for the cysteine feedstocks. Material is packed in foil-laminate bags, optionally nitrogen-flushed, and is best shipped and stored at 2-8 °C, under which conditions it holds specification for 24 months. Typical formats are capsules and tablets, sublingual and oral-film delivery, liposomal systems, effervescent and beauty-from-within drink powders, topical cosmetic bases, and glutathione affinity and redox buffers in bioprocessing. Export classification is HS 2930 90 99 as an organo-sulphur compound.