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ENZYME entry: EC 1.8.99.5

Accepted Name

Dissimilatory sulfite reductase.

Alternative Name(s)

Siroheme sulfite reductase.

Reaction catalysed

Hydrogen sulfide + a [DsrC protein]-disulfide + 2 acceptor + 3 H(2)O <=> sulfite + a [DsrC protein]-dithiol + 2 reduced acceptor + 2 H(+)
A [DsrC protein]-S-sulfanyl-L-cysteine + 3 acceptor + 3 H(2)O <=> sulfite + a [DsrC protein]-disulfide + 3 reduced acceptor + 2 H(+)

Cofactor(s)

Siroheme.

Comment(s)

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 catalyzes the reduction of sulfite to sulfide, while in sulfur oxidizers it catalyzes the opposite reaction.
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.
This enzyme is different from EC 1.8.1.2 and EC 1.8.7.1, which are involved in sulfate assimilation.

Cross-references

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature

IUBMB Enzyme Nomenclature

IntEnz

MEDLINE

MetaCyc

Rhea expert-curated reactions

UniProtKB/Swiss-Prot

O33998, DSRA_ALLVD;	Q59109, DSRA_ARCFU;	Q59110, DSRB_ARCFU;
P45575, DSVB_DESVH;	P94694, DSVB_MEGG1;	P45573, DSVC_DESVH;

All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc.

All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.8.99.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.8.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.-.-.-