TAILIEUCHUNG - Báo cáo khoa học: 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 thio-sulfate in three consecutive reactions has been identified in rat liver as well as in the body-wall tissue of the lugworm,Arenicola marina. | ễFEBS Journal Three enzymatic activities catalyze the oxidation of sulfide to thiosulfate in mammalian and invertebrate mitochondria Tatjana M. Hildebrandt and Manfred K. Grieshaber Institut fur Zoophysiologie Heinrich-Heine-Universitat Dusseldorf Germany Keywords mitochondria sulfide oxidation sulfide quinone oxidoreductase sulfur dioxygenase sulfur transferase Correspondence T. Hildebrandt Institut fur Zoophysiologie Heinrich-Heine-Universitat Dusseldorf 40225 Dusseldorf Germany Fax 49 211 811 1676 Tel 49 211 811 3577 E-mail @ Received 27 February 2008 revised 15 April2008 accepted 29 April 2008 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 membranebound 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. doi Hydrogen sulfide was known as a toxic pollutant long before its physiological functions became apparent. The main effects of sulfide poisoning are the loss of central respiratory drive due to lesions in the brain stem and inhibition of cytochrome oxidase leading to impaired aerobic energy metabolism 1 . Sulfide-rich environments occur naturally in the sediments and grass marshes

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