Figure 2. Hydrogen sulfide synthesis and effector ion channels .

Schematic diagram illustrating the synthesis of H₂S from homocysteine, l‐ and d‐cysteine via enzymes shown in boxes (CBS, cystathionine β synthase; CSE, cystathionine γ lyase; 3‐MST, 3‐mercaptopyruvate sulfurtransferase; CAT, cysteine aminotransferase; DAO, d‐amino acid oxidase). Some of the target ion channels modulated by H₂S are also indicated (NMDAR, N‐methyl‐ d‐aspartate receptor; K_ATP, ATP‐sensitive K⁺ channel; BK_Ca, large conductance K⁺ channel; VGCC, voltage‐gated Ca²⁺ channel; TRP, transient receptor potential channel).