Figure 2.

Sulfur assimilation and glutathione and phytochelatins synthesis in plants ATPS, ATP sulfurylase; APS, adenosine 5′ phosphosulphate; γ-ECS, γ-glutamyl cysteine synthetase; γ-EC, γ-glutamyl cysteine; GS, glutathione synthetase; GSH, reduced glutathione; GSSG, oxidized glutathione; GPx, GSH peroxidase; GR, GSH reductase; PCS, phytochelatin synthase; PCs, phytochelatins; GT, GSH-S-transferases; Xe, xenobiotic; GS-Xe, glutathione-xenobiotic complex. The reactions are not shown stochiometrically. GR uses the cofactor NADPH. The Cd²⁺-GSH complex formation (cadmium bis-glutathionate) is fast and spontaneous and does not require enzyme catalysis. Modified from [31].