Identification of H(2)S(3) and H(2)S produced by 3-mercaptopyruvate sulfurtransferase in the brain

Hydrogen polysulfides (H(2)S(n)) have a higher number of sulfane sulfur atoms than hydrogen sulfide (H(2)S), which has various physiological roles. We recently found H(2)S(n) in the brain. H(2)S(n) induced some responses previously attributed to H(2)S but with much greater potency than H(2)S. However, the number of sulfur atoms in H(2)S(n) and its producing enzyme were unknown. Here, we detected H(2)S(3) and H(2)S, which were produced from 3-mercaptopyruvate (3 MP) by 3-mercaptopyruvate sulfurtransferase (3MST), in the brain. High performance liquid chromatography with fluorescence detection (LC-FL) and tandem mass spectrometry (LC-MS/MS) analyses showed that H(2)S(3) and H(2)S were produced from 3 MP in the brain cells of wild-type mice but not 3MST knockout (3MST-KO) mice. Purified recombinant 3MST and lysates of COS cells expressing 3MST produced H(2)S(3) from 3 MP, while those expressing defective 3MST mutants did not. H(2)S(3) was localized in the cytosol of cells. H(2)S(3) was also produced from H(2)S by 3MST and rhodanese. H(2)S(2) was identified as a minor H(2)S(n), and 3 MP did not affect the H(2)S(5) level. The present study provides new insights into the physiology of H(2)S(3) and H(2)S, as well as novel therapeutic targets for diseases in which these molecules are involved.