1.8.3.1 additional information the enzyme is believed to detoxify excess sulfite that is produced during sulfur assimilation, or due to air pollution Arabidopsis thaliana ? - ? 89 1.8.3.1 additional information No activity is found with cytochrome c as electron acceptor, since the heme domain known to mediate electron transfer between the molybdenum cofactor-domain and cytochrome c in rat hepatic SO is missing in the plant enzyme Arabidopsis thaliana ? - ? 89 1.8.3.1 additional information the enzyme does not react with cytochrome c Arabidopsis thaliana ? - ? 89 1.8.3.1 additional information The optimal substrate or precise physiological role for YedYZ in Escherichia coli and its well-conserved orthologs in other bacteria remains unknown. Escherichia coli ? - ? 89 1.8.3.1 additional information Oax-Mo-Sthiolate-C dihedral angles near 90° effectively eliminate covalency contributions to the Mo(xy) redox orbital from the thiolate sulfur. The Oax-Mo-Sthiolate-C dihedral angle is shown to have a pronounced effect on the relative intensity ratios of the XAS spin-allowed S(1s)fSv(p) + Mo-(xy) and S(1s)fSv(p) + Mo(xz,yz) transitions synthetic construct ? - ? 89 1.8.3.1 additional information R138, R190, and R450 contribute to a positively charged binding pocket, which stabilizes substrate/product binding Gallus gallus ? - ? 89 1.8.3.1 additional information the plant sulfite oxidase does not accept cyctochrome c as substrate Spinacia oleracea ? - ? 89 1.8.3.1 additional information the plant sulfite oxidase does not accept cyctochrome c as substrate Syzygium cumini ? - ? 89 1.8.3.1 additional information the plant sulfite oxidase does not accept cyctochrome c as substrate Azadirachta indica ? - ? 89 1.8.3.1 additional information the plant sulfite oxidase does not accept cyctochrome c as substrate Cassia fistula ? - ? 89 1.8.3.1 additional information the plant sulfite oxidase does not accept cyctochrome c as substrate Saraca indica ? - ? 89 1.8.3.1 additional information mechanism of oxidation of sulfite and radical generation by ferric cytochrome c (Fe3+ cyt c) in the absence and presence of H2O2, oxidation of sulfite by the Fe3+ cyt c increased with sulfite concentration, overview Homo sapiens ? - ? 89 1.8.3.1 additional information reduced sulfite oxidase catalyzes single-electron transfer at molybdenum domain to reduce nitrite to nitric oxide. At physiological concentrations of nitrite, sulfite oxidase functions as nitrite reductase in the presence of a one-electron donor, exhibiting redox coupling of substrate oxidation and nitrite reduction to form NO. With sulfite, the physiological substrate, sulfite oxidase only facilitates one turnover of nitrite reduction. Nitrite reduction occurs at the molybdenum center via coupled oxidation of Mo(IV) to Mo(V). Reaction rates of nitrite to NO decreased in the presence of a functional heme domain, mediated by steric and redox effects of this domain. Nitrite binds to and is reduced at the molybdenum site of mammalian sulfite oxidase, which may be allosterically regulated by heme and molybdenum domain interactions, and contributes to the mammalian nitrate-nitrite-NO signaling pathway in human fibroblasts. Using phenosafranine or sulfite as reducing substrate, the Mo-domain shows much faster nitrite reduction to NO than holo-sulfite oxidase, catalytic Mo(IV) to Mo(V) nitrite reduction cycle, overview Homo sapiens ? - ? 89 1.8.3.1 additional information regeneration of the enzyme includes two, one-electron intramolecular electron transfers (IET) from the molybdenum (Mo) to the heme Fe and two, one-electron intermolecular electron transfers from the Fe to external ferricytochrome c Homo sapiens ? - ? 89 1.8.3.1 additional information sulfite ligand docking study Solanum lycopersicum ? - ? 89 1.8.3.1 additional information sulfite ligand docking study Populus trichocarpa ? - ? 89 1.8.3.1 additional information sulfite ligand docking study Brachypodium distachyon ? - ? 89 1.8.3.1 additional information sulfite ligand docking study, arginine residues particularly Arg374 is crucial for SOX-sulfite binding and two other residues Arg51 and Arg103 are also implicated to be important for SOX-sulfite bindings in plants Arabidopsis thaliana ? - ? 89 1.8.3.1 additional information the sulfite oxidase catalyzes single-electron transfer at molybdenum domain to reduce nitrite to nitric oxide. The SO Moco binding domain has the ability to oxidize sulfite in the presence of artificial electron acceptors like ferricyanide. The two-electron oxidation of sulfite to sulfate occurs at the molybdenum site, which is reduced from Mo(VI) to Mo(IV), followed by intramolecular electron transfer to the cytb5 site, with cytochrome c serving as the terminal electron acceptor. The movement of domains between the Moco domain and the cytb5 domain facilitated by the flexible linker is essential for efficient electron transfer between the heme and the Moco Homo sapiens ? - ? 89 1.8.3.1 nitrite + ferricytochrome c the enzyme can oxidize sulfite, and direct the electrons to reducing nitrite, to yield nitric oxide in the mitochondria Homo sapiens nitric oxide + ferrocytochrome c - ? 462837 1.8.3.1 nitrite + H2O + porcine ferricytochrome c the nitrite reduction mechanism involves sulfite oxidation, sulfate release and nitrite coordination at molybdenum with protonation-dependent nitric oxide and molybdenum V release. The highest nitric oxide production occurs between 0.01 and 0.0375 mM sulfite, with a dose-dependent inhibition of nitric oxide formation at higher sulfite concentrations Homo sapiens nitric oxide + porcine ferrocytochrome c - ? 462838 1.8.3.1 selenite + ferricyanide + H2O approximately 5% of the observed sulfite activity Arabidopsis thaliana ? + ferrocyanide - ? 385718 1.8.3.1 SO32- + H2O + 2 Fe(III)cytochrome c - Capra hircus SO42- + 2 Fe(II)cytochrome c + 2 H+ - ? 406668 1.8.3.1 SO32- + H2O + 2 ferricyanide - Capra hircus SO42- + 2 ferrocyanide + 2 H+ - ? 406669 1.8.3.1 SO32- + H2O + 2 ferricytochrome c - Rattus norvegicus SO42- + 2 ferrocytochrome c + 2 H+ - ? 406670 1.8.3.1 SO32- + H2O + O2 - Arabidopsis thaliana SO42- + H2O2 - ? 406672 1.8.3.1 SO32- + H2O + O2 - Gallus gallus SO42- + H2O2 - ? 406672 1.8.3.1 sodium sulfite + H2O + A - Malva sylvestris NaSO42- + AH2 - ? 385739 1.8.3.1 sulfite + cytochrome c - Gallus gallus sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c - Homo sapiens sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c - Rattus norvegicus sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c - vertebrata sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c detoxification vertebrata sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c detoxification Merluccius productus sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c genetic deficiency results in neurological abnormities Homo sapiens sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c catalytic cycle Gallus gallus sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c natural acceptor Rattus norvegicus sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c significantly slower activity than that observed with ferricyanide Arabidopsis thaliana sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + cytochrome c substrates horse heart cytochrome c, and recombinant Starkeya novella cytochrome c are only reduced to about 40% while Sinorhizobium meliloti cytochrome c is almost completely reduced. Enzyme interacts with two small redox proteins, a cytochrome c and a Cu containing pseudoazurin, that are encoded in the same operon and are co-transcribed with the sorT gene Sinorhizobium meliloti sulfate + reduced cytochrome c - ? 370185 1.8.3.1 sulfite + ferricyanide + H+ - Homo sapiens sulfate + reduced ferricyanide - ? 442003 1.8.3.1 sulfite + ferricyanide + H+ - Zea mays sulfate + reduced ferricyanide - ? 442003 1.8.3.1 sulfite + ferricyanide + H2O - Homo sapiens sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Spinacia oleracea sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Arabidopsis thaliana sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Hibiscus cannabinus sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Solanum lycopersicum sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Gallus gallus sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Syzygium cumini sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Azadirachta indica sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Cassia fistula sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Saraca indica sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + ferricyanide + H2O - Zea mays sulfate + ferrocyanide - ? 377838 1.8.3.1 sulfite + H2O + A - Thermus thermophilus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Homo sapiens SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Rattus norvegicus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Bos taurus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Spinacia oleracea SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Canis lupus familiaris SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Malva sylvestris SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Deinococcus radiodurans SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Acidithiobacillus thiooxidans SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Arabidopsis thaliana SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A artificial A: tetramethylphenylenediamine, 2,6-dichloroindophenol, methylene blue Rattus norvegicus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A H2O2 acceptor only when respiratory chain is inhibited Rattus norvegicus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A A: electron acceptor, i.e. O2, cytochrome c, K3[Fe(CN)6], 2,6-dichloroindophenol, methylene blue, highly specific for sulfite as electron donor Gallus gallus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A A: electron acceptor, i.e. O2, cytochrome c, K3[Fe(CN)6], 2,6-dichloroindophenol, methylene blue, highly specific for sulfite as electron donor Mus musculus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A A: electron acceptor, i.e. O2, cytochrome c, K3[Fe(CN)6], 2,6-dichloroindophenol, methylene blue, highly specific for sulfite as electron donor Rattus norvegicus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A A: electron acceptor, i.e. O2, cytochrome c, K3[Fe(CN)6], 2,6-dichloroindophenol, methylene blue, highly specific for sulfite as electron donor Bos taurus SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Acidithiobacillus thiooxidans NB1-3 SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Thermus thermophilus AT62 SO42- + AH2 - ? 259559 1.8.3.1 sulfite + H2O + A - Homo sapiens sulfate + AH2 - ? 401983 1.8.3.1 sulfite + H2O + A - Rattus norvegicus sulfate + AH2 - ? 401983 1.8.3.1 sulfite + H2O + A - synthetic construct sulfate + AH2 - ? 401983 1.8.3.1 sulfite + H2O + A the active site of the native enzyme can adopt both six-coordinate and five-coordinate geometries, which may be important in the catalytic mechanism, which may involve the binding of anions such as sulfite directly to Mo Homo sapiens sulfate + AH2 - ? 401983 1.8.3.1 sulfite + H2O + A the initial step in the oxygen-atom transfer reaction with HSO3- takes place by oxoanionic binding of the substrate to the MoVI center with the formation of a stable Michaelis complex synthetic construct sulfate + AH2 - ? 401983 1.8.3.1 sulfite + H2O + ferricyanide - Arabidopsis thaliana sulfate + ferrocyanide - ir 385781 1.8.3.1 sulfite + H2O + O2 - Arabidopsis thaliana sulfate + hydrogen peroxide - ? 385782 1.8.3.1 sulfite + H2O + porcine ferricyanide - Homo sapiens sulfate + porcine ferrocyanide - ? 463038 1.8.3.1 sulfite + H2O + porcine ferricytochrome c - Homo sapiens sulfate + porcine ferrocytochrome c - ? 463039 1.8.3.1 sulfite + O2 + H2O - Drosophila melanogaster sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Mus musculus sulfate + H2O2 - r 375316 1.8.3.1 sulfite + O2 + H2O - Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Rattus norvegicus sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Spinacia oleracea sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Nicotiana tabacum sulfate + H2O2 - r 375316 1.8.3.1 sulfite + O2 + H2O - Arabidopsis thaliana sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Solanum lycopersicum sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Gallus gallus sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Syzygium cumini sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Azadirachta indica sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Cassia fistula sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Saraca indica sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Zea mays sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Populus trichocarpa sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Brachypodium distachyon sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Zea mays subsp. mays sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O lack of active enzyme produces severe neurodegeneration and early death in humans Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O sulfite is the physiological substrate Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O the enzyme catalyzes the oxidation of sulfite to sulfate using ferricytochrome c as the physiological electron acceptor Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O under normal physiological conditions, SO catalyzes the oxidation of sulfite to sulfate with cytochrome c (cyt c) as oxidizing substrate Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O during the sulfite-sulfite oxidase-cytochrome c catalytic cycle, movement between the molybdenum and heme domain is required to enable efficient single-electron transfer from molybdenum via the heme b5 cofactor to cytochrome c Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O usage of Fe3+ oxidized cytochrome c from horse heart Homo sapiens sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Arabidopsis thaliana Col-0 sulfate + H2O2 - ? 375316 1.8.3.1 sulfite + O2 + H2O - Arabidopsis thaliana sulfate + hydrogen peroxide - ? 385783