Reduced glutathione (GSH)
Reduced glutathione (GSH) is the working, single-molecule form of glutathione, with a free thiol group on its cysteine that can neutralise oxidants. Once it has done that job it becomes oxidised glutathione (GSSG).
Also called GSH, glutathione (reduced form).
The abbreviation spells out its working part: the SH is the thiol, a sulphur atom bonded to hydrogen, which can hand electrons to an oxidant. Glutathione is the most abundant non-protein thiol in mammalian tissues (Lu 2013), and in a healthy cell most of it is held in this reduced form.
Cells use GSH to reduce oxidants and to bind foreign reactive chemicals so they can be removed (Forman 2009). Enzymes such as GPX4 draw on it to disarm oxidised fats in cell membranes.
How much GSH a cell holds depends on how fast it makes new glutathione and how fast it recycles the used form. In older adults, red blood cells made glutathione more slowly and held less of it than in younger adults (Sekhar 2011). In mouse cartilage cells, a pro-oxidant challenge raised glutathione content and the GSH:GSSG ratio, which the authors read as the cells strengthening their resistance to stress (Zhu 2020).
Sources
- Lu SC. Glutathione synthesis. Biochim Biophys Acta 2013.
- Forman HJ, Zhang H, Rinna A. Glutathione: overview of its protective roles, measurement, and biosynthesis. Mol Aspects Med 2009.
- Sekhar RV, Patel SG, Guthikonda AP et al. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr 2011.
- Zhu S, Makosa D, Miller B et al. Glutathione as a mediator of cartilage oxidative stress resistance and resilience during aging and osteoarthritis. Connect Tissue Res 2020.
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