DB code: D00498

CATH domain 1.10.760.10 : Cytochrome Bc1 Complex; Chain D, domain 2 Catalytic domain
2.140.10.20 : Methanol Dehydrogenase; Chain A Catalytic domain
E.C. 1.7.2.1 1.7.99.1 1.9.3.1
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
1.10.760.10 : Cytochrome Bc1 Complex; Chain D, domain 2 D00055 M00179
2.140.10.20 : Methanol Dehydrogenase; Chain A D00055

Uniprot Enzyme Name
UniprotKB Protein name Synonyms
P72181 Nitrite reductase
EC 1.7.2.1
Cytochrome cd1
Cytochrome oxidase
Hydroxylamine reductase
EC 1.7.99.1

KEGG enzyme name
nitrite reductase (NO-forming)
(EC 1.7.2.1 )
cd-cytochrome nitrite reductase
(EC 1.7.2.1 )
[nitrite reductase (cytochrome)] [misleading, see comments.]
(EC 1.7.2.1 )
cytochrome c-551:O2, NO2+ oxidoreductase
(EC 1.7.2.1 )
cytochrome cd
(EC 1.7.2.1 )
cytochrome cd1
(EC 1.7.2.1 )
hydroxylamine (acceptor) reductase
(EC 1.7.2.1 )
methyl viologen-nitrite reductase
(EC 1.7.2.1 )
nitrite reductase (cytochrome
(EC 1.7.2.1 )
NO-forming)
(EC 1.7.2.1 )
hydroxylamine reductase
(EC 1.7.99.1 )
hydroxylamine (acceptor) reductase
(EC 1.7.99.1 )
ammonia:(acceptor) oxidoreductase
(EC 1.7.99.1 )
cytochrome-c oxidase
(EC 1.9.3.1 )
cytochrome oxidase
(EC 1.9.3.1 )
cytochrome a3
(EC 1.9.3.1 )
cytochrome aa3
(EC 1.9.3.1 )
Warburg's respiratory enzyme
(EC 1.9.3.1 )
indophenol oxidase
(EC 1.9.3.1 )
indophenolase
(EC 1.9.3.1 )
complex IV (mitochondrial electron transport)
(EC 1.9.3.1 )
ferrocytochrome c oxidase
(EC 1.9.3.1 )
NADH cytochrome c oxidase
(EC 1.9.3.1 )

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P72181 NIRS_PARPN Nitric oxide + H(2)O + ferricytochrome c = nitrite + ferrocytochrome c + 2 H(+). NH(3) + H(2)O + acceptor = hydroxylamine + reduced acceptor. Homodimer. Periplasm. Binds 2 heme groups per subunit.

KEGG Pathways
Map code Pathways E.C.
MAP00190 Oxidative phosphorylation 1.9.3.1
MAP00910 Nitrogen metabolism 1.7.2.1 1.7.99.1

Compound table
Cofactors Substrates Products Intermediates
KEGG-id C00032 C00032 C00088 C00126 C00080 C00014 C00028 C00007 C00533 C00001 C00125 C00192 C00030
E.C. 1.7.2.1
1.7.99.1
1.9.3.1
1.7.2.1
1.7.99.1
1.9.3.1
1.7.2.1
1.7.2.1
1.9.3.1
1.7.2.1
1.9.3.1
1.7.99.1
1.7.99.1
1.9.3.1
1.7.2.1
1.7.2.1
1.7.99.1
1.9.3.1
1.7.2.1
1.9.3.1
1.7.99.1
1.7.99.1
Compound c heme d1 heme Nitrite Ferrocytochrome c H+ Ammonia Acceptor O2 Nitric oxide H2O Ferricytochrome c Hydroxylamine Reduced acceptor
Type aromatic ring (with nitrogen atoms),carboxyl group,heavy metal aromatic ring (with nitrogen atoms),carboxyl group,heavy metal others amide group,amine group,aromatic ring (with nitrogen atoms),carboxyl group,heavy metal,sulfide group others amine group,organic ion others others others H2O amide group,amine group,aromatic ring (with nitrogen atoms),carboxyl group,heavy metal,sulfide group amine group others
ChEBI 17627
 26355
 17627
 26355
 		17627
 26355
 17627
 26355
 		25567
 25567
 		15378
 15378
 		16134
 16134
 		15379
 26689
 27140
 15379
 26689
 27140
 		16480
 16480
 		15377
 15377
 		15429
 15429
PubChem 24529
 24529
 		1038
 1038
 		222
 222
 		977
 977
 		145068
 145068
 		22247451
 962
 22247451
 962
 		787
 787
1aofA01 Bound:HEM Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aofB01 Bound:HEM Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aomB01 Bound:HEM Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aoqA01 Bound:HEM Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aoqB01 Bound:HEM Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1dy7B01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1e2rA01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1e2rB01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1gq1A01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1gq1B01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9xA01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9xB01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9yA01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9yB01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hcmA01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hcmB01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj3A01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj3B01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj4A01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj4B01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj5A01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj5B01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1qksA01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1qksB01 Bound:HEC Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aofA02 Unbound Bound:DHE Analogue:SO2 Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aofB02 Unbound Bound:DHE Analogue:SO2 Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aomA02 Unbound Bound:DHE Bound:2NO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aomB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Bound:_NO Unbound Unbound Unbound
1aoqA02 Unbound Bound:DHE Bound:2NO Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1aoqB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Bound:_NO Unbound Unbound Unbound
1dy7A02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CMO Unbound Unbound Unbound
1dy7B02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CMO Unbound Unbound Unbound
1e2rA02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CYN Unbound Unbound Unbound
1e2rB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CYN Unbound Unbound Unbound
1gq1A02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1gq1B02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9xA02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9xB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1h9yA02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CYN Unbound Unbound Unbound
1h9yB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Analogue:CYN Unbound Unbound Unbound
1hcmA02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hcmB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj3A02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj3B02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Bound:OXY Unbound Unbound Unbound Unbound
1hj4A02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj4B02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj5A02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hj5B02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1qksA02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1qksB02 Unbound Bound:DHE Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1aofA01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-35
1aofB01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-35
1aomB01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1aoqA01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1aoqB01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1dy7B01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-31
1e2rA01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-35
1e2rB01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-35
1gq1A01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent); mutant Y25S
1gq1B01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent); mutant Y25S
1h9xA01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-41
1h9xB01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-41
1h9yA01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-47
1h9yB01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-47
1hcmA01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-41
1hcmB01 ;HIS 69;MET 106(Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-41
1hj3A01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1hj3B01 ;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-25
1hj4A01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1hj4B01 ;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent); truncated 1-25
1hj5A01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1hj5B01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1qksA01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1qksB01 HIS 17;HIS 69; (Heme c axial binding);CYS 65;CYS 68(Heme c covalent);TYR 25(Heme d1)
1aofA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1aofB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1aomA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1aomB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1aoqA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1aoqB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1dy7A02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1dy7B02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1e2rA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1e2rB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1gq1A02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1gq1B02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1h9xA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1h9xB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1h9yA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1h9yB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hcmA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hcmB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj3A02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj3B02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj4A02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj4B02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj5A02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1hj5B02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1qksA02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)
1qksB02 HIS 345;HIS 388 HIS 200(Heme d1 proximal binding)

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[1]
Fig.7, p.373-374
[3]
p.442-446
[4]
[5]
Fig.3, p.236-239
[6]
p.4034-4035
[8]
Fig.6, p.10972-10974
[11]
Fig.4
[12]
p.1007-1008
[13]
[14]
p.13075-13076

References
[1]
Resource
Comments
Medline ID
PubMed ID 7736589
Journal Cell
Year 1995
Volume 81
Pages 369-77
Authors Fulop V, Moir JW, Ferguson SJ, Hajdu J
Title The anatomy of a bifunctional enzyme: structural basis for reduction of oxygen to water and synthesis of nitric oxide by cytochrome cd1.
Related PDB 1qks
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 9405061
Journal Biochemistry
Year 1997
Volume 36
Pages 16267-76
Authors Cheesman MR, Ferguson SJ, Moir JW, Richardson DJ, Zumft WG, Thomson AJ
Title Two enzymes with a common function but different heme ligands in the forms as isolated. Optical and magnetic properties of the heme groups in the oxidized forms of nitrite reductase, cytochrome cd1, from Pseudomonas stutzeri and Thiosphaera pantotropha.
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 9199411
Journal J Mol Biol
Year 1997
Volume 269
Pages 440-55
Authors Baker SC, Saunders NF, Willis AC, Ferguson SJ, Hajdu J, Fulop V
Title Cytochrome cd1 structure: unusual haem environments in a nitrite reductase and analysis of factors contributing to beta-propeller folds.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 9311786
Journal Nature
Year 1997
Volume 389
Pages 406-12
Authors Williams PA, Fulop V, Garman EF, Saunders NF, Ferguson SJ, Hajdu J
Title Haem-ligand switching during catalysis in crystals of a nitrogen-cycle enzyme.
Related PDB 1aof 1aom 1aoq
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 10320660
Journal Biochim Biophys Acta
Year 1999
Volume 1411
Pages 231-49
Authors Cutruzzola F
Title Bacterial nitric oxide synthesis.
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 10747791
Journal Biochemistry
Year 2000
Volume 39
Pages 4028-36
Authors Koppenhofer A, Little RH, Lowe DJ, Ferguson SJ, Watmough NJ
Title Oxidase reaction of cytochrome cd(1) from Paracoccus pantotrophus.
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 10757972
Journal Biochemistry
Year 2000
Volume 39
Pages 4243-9
Authors Koppenhofer A, Turner KL, Allen JW, Chapman SK, Ferguson SJ
Title Cytochrome cd(1) from Paracoccus pantotrophus exhibits kinetically gated, conformationally dependent, highly cooperative two-electron redox behavior.
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 10998233
Journal Biochemistry
Year 2000
Volume 39
Pages 10967-74
Authors Sjogren T, Svensson-Ek M, Hajdu J, Brzezinski P
Title Proton-coupled structural changes upon binding of carbon monoxide to cytochrome cd1: a combined flash photolysis and X-ray crystallography study.
Related PDB 1dy7
Related UniProtKB
[9]
Resource
Comments
Medline ID
PubMed ID 10827177
Journal J Biol Chem
Year 2000
Volume 275
Pages 25089-94
Authors Jafferji A, Allen JW, Ferguson SJ, Fulop V
Title X-ray crystallographic study of cyanide binding provides insights into the structure-function relationship for cytochrome cd1 nitrite reductase from Paracoccus pantotrophus.
Related PDB 1e2r
Related UniProtKB
[10]
Resource
Comments
Medline ID
PubMed ID 10708389
Journal Microbiology
Year 2000
Volume 146
Pages 509-16
Authors Saunders NF, Ferguson SJ, Baker SC
Title Transcriptional analysis of the nirS gene, encoding cytochrome cd1 nitrite reductase, of Paracoccus pantotrophus LMD 92.63.
Related PDB
Related UniProtKB
[11]
Resource
Comments
Medline ID
PubMed ID 11062553
Journal Nat Struct Biol
Year 2000
Volume 7
Pages 1006-12
Authors Hajdu J, Neutze R, Sjogren T, Edman K, Szoke A, Wilmouth RC, Wilmot CM
Title Analyzing protein functions in four dimensions.
Related PDB
Related UniProtKB
[12]
Resource
Comments
Medline ID
PubMed ID 11373294
Journal J Biol Chem
Year 2001
Volume 276
Pages 29450-5
Authors Sjogren T, Hajdu J
Title The Structure of an alternative form of Paracoccus pantotrophus cytochrome cd(1) nitrite reductase.
Related PDB 1h9x 1h9y 1hcm
Related UniProtKB
[13]
Resource
Comments
Medline ID
PubMed ID 11278884
Journal J Biol Chem
Year 2001
Volume 276
Pages 13072-6
Authors Sjogren T, Hajdu J
Title Structure of the bound dioxygen species in the cytochrome oxidase reaction of cytochrome cd1 nitrite reductase.
Related PDB 1hj3 1hj4 1hj5
Related UniProtKB
[14]
Resource
Comments
Medline ID
PubMed ID 11035020
Journal J Biol Chem
Year 2001
Volume 276
Pages 5846-55
Authors Steensma E, Gordon E, Oster LM, Ferguson SJ, Hajdu J
Title Heme ligation and conformational plasticity in the isolated c domain of cytochrome cd1 nitrite reductase.
Related PDB
Related UniProtKB
[15]
Resource
Comments
Medline ID
PubMed ID 12086580
Journal Biochem J
Year 2002
Volume 366
Pages 883-8
Authors Allen JW, Higham CW, Zajicek RS, Watmough NJ, Ferguson SJ
Title A novel, kinetically stable, catalytically active, all-ferric, nitrite-bound complex of Paracoccus pantotrophus cytochrome cd1.
Related PDB
Related UniProtKB
[16]
Resource
Comments
Medline ID
PubMed ID 12556530
Journal J Biol Chem
Year 2003
Volume 278
Pages 11773-81
Authors Gordon EH, Sjogren T, Lofqvist M, Richter CD, Allen JW, Higham CW, Hajdu J, Fulop V, Ferguson SJ
Title Structure and kinetic properties of Paracoccus pantotrophus cytochrome cd1 nitrite reductase with the d1 heme active site ligand tyrosine 25 replaced by serine.
Related PDB 1gq1
Related UniProtKB

Comments
This structure contains a heme protein, cytochrome cd1.
Although this enzyme is homologous to the counterpart from Pseudomonas aeriginosa (Swiss-prot; P24474, D00055 in EzCatDB), the active site residues and positions are slightly different from that. In this enzyme, c heme iron coordination can change from His17/His69 to Met106/His69, whereas the counterpart enzyme has got c heme iron coordination with Met88/His51. Moreover, the counterpart enzyme does not have a residue corresponding to Tyr25 in this enzyme.
Although only two E.C. numbers (1.7.2.1 and 1.7.99.1) have been annotated in Swiss-prot data (Swiss-prot; P72181), this enzyme also seems to catalyze the reaction, corresponding to E.C. 1.9.3.1, according to the literature.
Thus, this enzyme catalyzes the following reactions:
(a) NO2(-) + 2 H(+) + e- = NO + H2O
(b) NH3 + H2O + acceptor = hydroxylamine + reduced acceptor.
(c) O2 + 4 H(+) + 4 e- = 2 H2O
#####
There are some other kind of "nitrite reductases":
E.C. 1.7.1.4 nitrite reductase [NAD(P)H]
E.C. 1.7.2.2 nitrite reductase (cytochrome; ammonia-forming)
E.C. 1.7.7.1 ferredoxin-nitrite reductase
Another nitrite reductase enzyme (E.C. 1.7.2.1) which contains multiple copper centres, is described in D00449 in EzCatDB.

Created Updated
2005-07-05 2009-02-26