Figure 2.

S-Sulfuration of cysteine residues by H₂S and H₂S_n. Cysteine residues are S-sulfenylated by H₂O₂ and S-nitrosylated by NO. These oxidized cysteine residues are S-sulfurated by H₂S. In contrast, cysteine residues are S-sulfurated by H₂S_n.