Three enzymatic activities catalyze the oxidation of sulfide to thiosulfate in mammalian and invertebrate mitochondria.
Hydrogen sulfide is a potent toxin of aerobic respiration, but also has physiological functions as a signalling molecule and as a substrate for ATP production. A mitochondrial pathway catalyzing sulfide oxidation to thiosulfate in three consecutive reactions has been identified in rat liver as well as in the body-wall tissue of the lugworm, Arenicola marina. A membrane-bound sulfide : quinone oxidoreductase converts sulfide to persulfides and transfers the electrons to the ubiquinone pool. Subsequently, a putative sulfur dioxygenase in the mitochondrial matrix oxidizes one persulfide molecule to sulfite, consuming molecular oxygen. The final reaction is catalyzed by a sulfur transferase, which adds a second persulfide from the sulfide : quinone oxidoreductase to sulfite, resulting in the final product thiosulfate. This role in sulfide oxidation is an additional physiological function of the mitochondrial sulfur transferase, rhodanese.
Hildebrandt
Tatjana M
TM
Institut für Zoophysiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany. tatjana.hildebrandt@uni-duesseldorf.de
Grieshaber
Manfred K
MK
D000818:Animals; D000845:Annelida; D002384:Catalysis; D006862:Hydrogen Sulfide / Q000737:chemistry; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology* / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology* / Q000378:metabolism*; D008954:Models, Biological; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D011808:Quinone Reductases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013045:Species Specificity; D013440:Sulfides / Q000737:chemistry*; D013884:Thiosulfate Sulfurtransferase / Q000378:metabolism
D013440:Sulfides; D011808:Quinone Reductases; D013884:Thiosulfate Sulfurtransferase; D010100:Oxygen; D006862:Hydrogen Sulfide