PathwayStep859 PathwayStep2602 PathwayStep2601 PathwayStep2600 PathwayStep2599 PathwayStep2598 Sulfide oxidation to sulfate Authored: Stephan, R, 2010-10-24 Edited: Jassal, B, 2011-09-29 GENE ONTOLOGYGO:0070221 Pubmed20162368 Reactome Database ID Release 431614517 Reactome, http://www.reactome.org ReactomeREACT_116010 Reviewed: D'Eustachio, P, 2011-10-13 While the human body is very economical with sulfur amino acids (SAA), superfluous SAA are degraded via cysteine to toxic hydrogen sulfide which must be dealt with. The pathway to oxidize this gas is localized to mitochondria and is highly conserved, pointing back to a time when life was immersed in sulfide-rich waters.<br>The pathway for sulfide oxidation consists of five reactions, one of which, the sulfur transfer from thiosulfate to glutathione, is still to be characterized fully. A mutation in one enzyme has been identified that is associated with ethylmalonyl encephalopathy and where tissue sulfide is elevated (Stipanuk & Ueki 2011). Sulfate is exported to the cytosol in exchange for dicarboxylate SQR oxidizes sulfide to bound persulfide Persulfide sulfur is transferred onto sulfite Persulfide sulfur is dioxygenated Sulfite is oxidized to sulfate Thiosulfate can transfer its sulfate to glutathione