L-Buthionine- (S,R)-Sulfoximine

L-Buthionine-(S,R)-Sulfoximine is a potent, fast acting, irreversible inhibitor of gamma-glutamylcysteine synthetase the rate-limiting enzyme for L-glutathione (GSH) synthesis, that induces oxidative stress in cells by depleting GSH. Shown to improve the outcome of chemotherapy by lowering the levels of glutathione in cancer cells.