Phytochelatins (PCs) are a family of thiol-rich peptides, with the general structure (γ-Glu-Cys) n -Gly, with n = 2−11, induced in plants upon exposure to excessive amounts of heavy metals and some metalloids, such as arsenic. Studies with Cd(II), Hg(II), and Pb(II) show that the synthetic (Glu-Cys)2Gly peptide exhibits metal-chelating properties similar to the phytochelatin (γ Glu-Cys)2Gly.