CBS is a redox-sensitive enzyme at the junction of important pathways: methionine metabolism, transsulfuration, and glutathione synthesis. AHCY, adenosylhomocysteinase; CSE, cystathionine gamma-lyase; GCL, glutamate cysteine ligase; GS, GSH synthetase; MAT, methionine adenosyltransferase; MS, methionine synthase; MT, methyl transferase.