Production of H₂S by 3-mercaptopyruvate sulphurtransferase

Hydrogen sulfide (H₂S) has been established as the third gaseous signaling molecule following nitric oxide and carbon monoxide and participates in a variety of cellular functions such as modulation of neuronal transmission, endothelium-dependent vasorelaxation, stimulation of angiogenesis and regulation of insulin release. Although cystathionine β-synthase and cystathionine γ-lyase have been regarded as the main producers of H₂S in many tissues including brain, liver and kidney, Kimura and his colleagues have recently communicated that 3-mercaptopyruvate sulphurtransferase coupled with cysteine (aspartate) aminotransferase is responsible for the production of H₂S in the vascular endothelium of the thoracic aorta [Shibuya et al. (2009) J. Biochem.146, 623–626]. This finding provides a new insight into the production of the physiologically important signaling molecule.