title: Organization of the human mitochondrial hydrogen sulfide oxidation pathway.
abstract: Sulfide oxidation is expected to play an important role in cellular switching between low steady-state intracellular hydrogen sulfide levels and the higher concentrations where the physiological effects are elicited. Yet despite its significance, fundamental questions regarding how the sulfide oxidation pathway is wired remain unanswered, and competing proposals exist that diverge at the very first step catalyzed by sulfide quinone oxidoreductase (SQR). We demonstrate that, in addition to sulfite, glutathione functions as a persulfide acceptor for human SQR and that rhodanese preferentially synthesizes rather than utilizes thiosulfate. The kinetic behavior of these enzymes provides compelling evidence for the flow of sulfide via SQR to glutathione persulfide, which is then partitioned to thiosulfate or sulfite. Kinetic simulations at physiologically relevant metabolite concentrations provide additional support for the organizational logic of the sulfide oxidation pathway in which glutathione persulfide is the first intermediate formed.
authors.affiliation: From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and.
authors.forename: Marouane
authors.initials: M
authors.lastname: Libiad
authors.affiliation: From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and.
authors.forename: Pramod Kumar
authors.initials: PK
authors.lastname: Yadav
authors.affiliation: From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and.
authors.forename: Victor
authors.initials: V
authors.lastname: Vitvitsky
authors.affiliation: the National Research Center for Hematology, Moscow 125167, Russia.
authors.forename: Michael
authors.initials: M
authors.lastname: Martinov
authors.affiliation: From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600 and rbanerje@umich.edu.
authors.forename: Ruma
authors.initials: R
authors.lastname: Banerjee
mesh_terms: D002384:Catalysis; D003545:Cysteine / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology; D005978:Glutathione / Q000737:chemistry; D006706:Homeostasis; D006801:Humans; D006862:Hydrogen Sulfide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008928:Mitochondria / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D011808:Quinone Reductases / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry
chemical_list: D013440:Sulfides; C051552:persulfides; D045304:Cytochromes c; D011808:Quinone Reductases; C073412:sulfide quinone reductase; D013884:Thiosulfate Sulfurtransferase; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen; D006862:Hydrogen Sulfide
keywords: Enzyme Kinetics; Flavoprotein; Hydrogen Sulfide; Oxidation-Reduction (Redox); Quinone; Redox