EC                 Enzyme                                 

dissimilatory sulfite reductase;
siroheme sulfite reductase;
hydrogen-sulfide:(acceptor) oxidoreductase (ambiguous);
Acting on a sulfur group of donors;
With unknown physiological acceptors
hydrogen-sulfide:[DsrC sulfur-carrier protein],acceptor oxidoreductase
(1) hydrogen sulfide + a [DsrC protein]-disulfide + 2 acceptor + 3 H2O = sulfite + a [DsrC protein]-dithiol + 2 reduced acceptor + 2 H+ (overall reaction) [RN:R00861];
(1a) hydrogen sulfide + a [DsrC protein]-disulfide = a [DsrC protein]-S-sulfanyl-L-cysteine;
(1b) a [DsrC protein]-S-sulfanyl-L-cysteine + 2 acceptor + 3 H2O = sulfite + a [DsrC protein]-dithiol + 2 reduced acceptor + 2 H+;
(2) a [DsrC protein]-S-sulfanyl-L-cysteine + 3 acceptor + 3 H2O = sulfite + a [DsrC protein]-disulfide + 3 reduced acceptor + 2 H+ (overall reaction);
(2a) a [DsrC protein]-S-sulfanyl-L-cysteine + 3 acceptor + 3 H2O = a [DsrC]-S-sulfo-L-cysteine + 3 reduced acceptor + H+;
(2b) a [DsrC]-S-sulfo-L-cysteine = sulfite + a [DsrC protein]-disulfide
(other) R00295 R08035
hydrogen sulfide [CPD:C00283];
[DsrC protein]-disulfide;
acceptor [CPD:C00028];
H2O [CPD:C00001];
[DsrC protein]-S-sulfanyl-L-cysteine;
sulfite [CPD:C00094];
[DsrC protein]-dithiol;
reduced acceptor [CPD:C00030];
H+ [CPD:C00080];
[DsrC protein]-S-sulfanyl-L-cysteine;
[DsrC protein]-disulfide;
Contain siroheme. The enzyme is essential in prokaryotic sulfur-based energy metabolism, including sulfate/sulfite reducing organisms, sulfur-oxidizing bacteria, and organosulfonate reducers. In sulfur reducers it catalyses the reduction of sulfite to sulfide (reaction 1 in the right to left direction), while in sulfur oxidizers it catalyses the opposite reaction (reaction 2 in the left to right direction) [1]. The reaction involves the small protein DsrC, which is present in all the organisms that contain dissimilatory sulfite reductase. During the process an intramolecular disulfide bond is formed between two L-cysteine residues of DsrC. This disulfide can be reduced by a number of proteins including DsrK and TcmB [5]. This enzyme is different from EC, assimilatory sulfite reductase (NADPH), and EC, assimilatory sulfite reductase (ferredoxin), which are involved in sulfate assimilation.
EC created 2015
ec00633  Nitrotoluene degradation
ec00920  Sulfur metabolism
ec01100  Metabolic pathways
ec01120  Microbial metabolism in diverse environments
K11180  dissimilatory sulfite reductase alpha subunit
K11181  dissimilatory sulfite reductase beta subunit
TIG: THII_0611 THII_0612
ALV: Alvin_1251(dsrA) Alvin_1252(dsrB)
TVI: Thivi_0544 Thivi_0545
TMB: Thimo_0143 Thimo_0144
MPUR: MARPU_10910 MARPU_10915
TSY: THSYN_22540 THSYN_22545
TTP: E6P07_09385(dsrB) E6P07_09390(dsrA)
AEH: Mlg_1653 Mlg_1654
HHA: Hhal_1951 Hhal_1952
HHK: HH1059_16540(dsrA-2) HH1059_16550(dsrB-1)
TNI: TVNIR_0859(dsrB_[H]) TVNIR_0860 TVNIR_1766 TVNIR_1767(dsvB_[H])
ACII: C4901_06765(dsrA) C4901_06770(dsrB)
TBN: TBH_C2461(dsrB) TBH_C2462(dsrA)
REV: HUE57_11060(dsrB) HUE57_11065(dsrA)
VOK: COSY_0794(dsrB) COSY_0795(dsrA)
EBH: BSEPE_1260(dsrB) BSEPE_1261(dsrA)
ENM: EBS_1783(dsrB) EBS_1784(dsrA)
SHD: SUTH_01443(dsrB) SUTH_01444(dsrA)
SDR: SCD_n02074(dsrA) SCD_n02717(dsrB) SCD_n02718(dsrA)
DVU: DVU0402(dsvA) DVU0403(dvsB)
DHY: DESAM_20116(dsvB) DESAM_20117(dsvA)
DGG: DGI_0689(dsrB) DGI_0691(dsrA)
DEF: CNY67_09565(dsrA) CNY67_09570(dsrB) CNY67_15020(dsrB) CNY67_15025(dsrA)
DTR: RSDT_0579(dsrB) RSDT_0580(dsrA)
DCB: C3Y92_18590(dsrB) C3Y92_18595(dsrA)
DPI: BN4_12627(dsrA) BN4_12628(dsrB)
PPRF: DPRO_1445(dsvB) DPRO_1446(dsvA)
PSEL: GM415_02165(dsrB) GM415_02170(dsrA)
DRT: Dret_0244(dsrA) Dret_0245(dsrB)
DML: Dmul_28170(dsrB) Dmul_28180(dsrA)
DAT: HRM2_42390(dsrB2) HRM2_42400(dsrA2)
DTO: TOL2_C05570(dsrA) TOL2_C05580(dsrB)
DOV: DSCO28_40940(dsvA) DSCO28_40950(dsvB)
DWD: DSCW_41400(dsvA) DSCW_41410(dsvB)
DALK: DSCA_41750(dsvB) DSCA_41760(dsvA)
DAX: FDQ92_05050(dsrB) FDQ92_05055(dsrA)
BLAG: BLTE_30830(dsrB-1) BLTE_30840(dsrA-2)
MGY: MGMSRv2__3911(dsrB) MGMSRv2__3912(dsrA)
MGRY: MSR1_25020(dsvA) MSR1_25030(dsvB)
MAGX: XM1_4244(dsrA) XM1_4245(dsrB)
MAGQ: MGMAQ_2110(dsrA) MGMAQ_2111(dsrB)
DSY: DSY0309(dsrA) DSY0310(dsrB)
CHY: CHY_2409(dsrB) CHY_2410(dsrA)
MTHO: MOTHE_c15990(dsvB1) MOTHE_c16000(dsvA1) MOTHE_c16350(dsvB2) MOTHE_c16360(dsvA2)
MTHZ: MOTHA_c16820(dsvB1) MOTHA_c16830(dsvA1) MOTHA_c17180(dsvB2) MOTHA_c17190(dsvA2)
CTE: CT0852(dsrA-1) CT0853(dsrB-1) CT2249(dsrA-2)
PROC: Ptc2401_00028(dsvA) Ptc2401_00029(dsvB)
PROS: CHL67_00155(dsrA) CHL67_00160(dsrB)
TYE: THEYE_A1994(dsrA) THEYE_A1995(dsrB)
THET: F1847_01210(dsrA) F1847_01215(dsrB)
TAV: G4V39_07740(dsrA) G4V39_07745(dsrB)
TMAI: FVE67_07900(dsrA) FVE67_07905(dsrB)
TTN: TTX_0423(dsrA) TTX_0424(dsrA) TTX_0426(dsrA) TTX_0427(dsrA) TTX_1187(dsrB) TTX_1188(dsrA)
 » show all
Schedel, M., Vanselow, M. and Trueper, H. G.
Siroheme sulfite reductase from Chromatium vinosum. Purification and investigation of some of its molecular and catalytic properties.
Arch Microbiol 121:29-36 (1979)
2  [PMID:7338517]
Seki Y, Sogawa N, Ishimoto M
Siroheme as an active catalyst in sulfite reduction.
J Biochem 90:1487-92 (1981)
3  [PMID:9695921]
Pott AS, Dahl C.
Sirohaem sulfite reductase and other proteins encoded by genes at the dsr locus of Chromatium vinosum are involved in the oxidation of intracellular sulfur.
Microbiology 144 ( Pt 7):1881-94 (1998)
4  [PMID:18829451]
Oliveira TF, Vonrhein C, Matias PM, Venceslau SS, Pereira IA, Archer M
The crystal structure of Desulfovibrio vulgaris dissimilatory sulfite reductase bound to DsrC provides novel insights into the mechanism of sulfate respiration.
J Biol Chem 283:34141-9 (2008)
5  [PMID:24662917]
Venceslau SS, Stockdreher Y, Dahl C, Pereira IA
The "bacterial heterodisulfide" DsrC is a key protein in dissimilatory sulfur metabolism.
Biochim Biophys Acta 1837:1148-64 (2014)
Other DBs
ExplorEnz - The Enzyme Database:
IUBMB Enzyme Nomenclature:
ExPASy - ENZYME nomenclature database:
BRENDA, the Enzyme Database:
CAS: 37256-51-2

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