Glutathione synthetase
Glutathione synthetase is the enzyme that carries out the second and final step of glutathione synthesis, adding glycine to gamma-glutamylcysteine to make finished glutathione.
Also called GSH synthetase, GS, GSS (its gene).
It follows glutamate cysteine ligase, the rate-limiting first enzyme, and the two are regulated at several levels, often together, with Nrf2 among the transcription factors that control them (Lu 2013).
Because glycine is added at this step, glycine supply matters too. Older adults with low red-cell glycine made glutathione more slowly than younger adults, and two weeks of glycine with cysteine restored their synthesis rate (Sekhar 2011).
Sources
- Lu SC. Glutathione synthesis. Biochim Biophys Acta 2013.
- 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.
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