Sulfite reductase - Misplaced Pages

Sulfite reductases (EC 1.8.99.1) are enzymes that participate in sulfur metabolism. They catalyze the reduction of sulfite to hydrogen sulfide and water. Electrons for the reaction are provided by a dissociable molecule of either NADPH, bound flavins, or ferredoxins.

SO₃ (sulfite) + electron donor $\rightleftharpoons$ H₂S (hydrogen sulfide) + oxidized donor + 3 H₂O

Sulfite reductases, which belong to the oxidoreductase family, are found in the archaea, bacteria, fungi, and plants. They are grouped as either the assimilatory or the dissimilatory sulfite reductases depending on their function, their spectroscopic properties, and their catalytic properties. This enzyme participates in selenoamino acid metabolism and sulfur assimilation. It employs two covalently coupled cofactors - an iron sulfur cluster and a siroheme - which the deliver electrons to the substrate via this coupling.

The systematic name of this enzyme class is hydrogen-sulfide:acceptor oxidoreductase. Other names in common use include assimilatory sulfite reductase, assimilatory-type sulfite reductase, and hydrogen-sulfide:(acceptor) oxidoreductase.

References

PDB: 1AOP; Crane BR, Siegel LM, Getzoff ED (October 1995). "Sulfite reductase structure at 1.6 A: evolution and catalysis for reduction of inorganic anions". Science. 270 (5233): 59–67. Bibcode:1995Sci...270...59C. doi:10.1126/science.270.5233.59. PMID 7569952. S2CID 31246227.
^ Parey K, Warkentin E, Kroneck PM, Ermler U (October 2010). "Reaction cycle of the dissimilatory sulfite reductase from Archaeoglobus fulgidus". Biochemistry. 49 (41): 8912–21. doi:10.1021/bi100781f. PMID 20822098.
Pinto R, Harrison JS, Hsu T, Jacobs WR, Leyh TS (September 2007). "Sulfite reduction in mycobacteria". Journal of Bacteriology. 189 (18): 6714–22. doi:10.1128/JB.00487-07. PMC 2045171. PMID 17644602.
Siegel LM, Murphy MJ, Kamin H (January 1973). "Reduced nicotinamide adenine dinucleotide phosphate-sulfite reductase of enterobacteria. I. The Escherichia coli hemoflavoprotein: molecular parameters and prosthetic groups". The Journal of Biological Chemistry. 248 (1): 251–64. doi:10.1016/S0021-9258(19)44469-4. PMID 4144254.
Brychkova G, Yarmolinsky D, Ventura Y, Sagi M (August 2012). "A novel in-gel assay and an improved kinetic assay for determining in vitro sulfite reductase activity in plants". Plant & Cell Physiology. 53 (8): 1507–16. doi:10.1093/pcp/pcs084. PMID 22685081.
Yarmolinsky D, Brychkova G, Kurmanbayeva A, Bekturova A, Ventura Y, Khozin-Goldberg I, Eppel A, Fluhr R, Sagi M (August 2014). "Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants". Plant Physiology. 165 (4): 1505–1520. doi:10.1104/pp.114.241356. PMC 4119034. PMID 24987017.
Schnell R, Sandalova T, Hellman U, Lindqvist Y, Schneider G (July 2005). "Siroheme- and [Fe4-S4]-dependent NirA from Mycobacterium tuberculosis is a sulfite reductase with a covalent Cys-Tyr bond in the active site". The Journal of Biological Chemistry. 280 (29): 27319–28. doi:10.1074/jbc.M502560200. PMID 15917234.
Crane BR, Getzoff ED (December 1996). "The relationship between structure and function for the sulfite reductases". Current Opinion in Structural Biology. 6 (6): 744–56. doi:10.1016/S0959-440X(96)80003-0. PMID 8994874.

Asada K (August 1967). "Purification and properties of a sulfite reductase from leaf tissue". The Journal of Biological Chemistry. 242 (16): 3646–54. doi:10.1016/S0021-9258(18)95858-8. PMID 6038492.
Asada K, Tamura G, Bandurski RS (September 1969). "Methyl viologen-linked sulfite reductase from spinach leaves". The Journal of Biological Chemistry. 244 (18): 4904–15. doi:10.1016/S0021-9258(18)94289-4. PMID 5824566.
Yoshimoto A, Nakamura T, Sato R (December 1967). "Isolation from Aspergillus nidulans, of a protein catalyzing the reduction of sulfite by reduced viologen dyes". Journal of Biochemistry. 62 (6): 756–66. doi:10.1093/oxfordjournals.jbchem.a128732. PMID 5589532.

v t e Oxidoreductases: sulfur oxidoreductases (EC 1.8)
1.8.1: NAD or NADP	Dihydrolipoamide dehydrogenase Glutathione reductase Thioredoxin reductase
1.8.2: cytochrome	Sulfite dehydrogenase Thiosulfate dehydrogenase Flavocytochrome c sulfide dehydrogenase
1.8.3: oxygen	Sulfite oxidase
1.8.4: disulfide	Glutathione—homocystine transhydrogenase
1.8.5: quinone	Glutathione dehydrogenase (ascorbate)
1.8.98: Other, known	CoB—CoM heterodisulfide reductase
1.8.99: Other	Sulfite reductase

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)

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