Gamma-glutamylcysteine synthetase (γ-GCS) is the rate limiting enzyme for glutathione (L-γ-glutamyl-L-cysteinylglycine, GSH) synthesis. GSH is ubiquitous in mammalian cells as a vital intra- and extracellular protective antioxidant. γ-GCS is a heterodimer of a heavy catalytic subunit and a light regulatory subunit that is responsive to inflammation, phenolic ntioxidants, heat shock, oxidants and cytokines.
