Information on EC 1.9.6.1 - nitrate reductase (cytochrome)

Word Map on EC 1.9.6.1
Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
Specify your search results
Select one or more organisms in this record:
Show additional data
Do not include text mining results
Include (text mining) results (more...)
Include results (AMENDA + additional results, but less precise; more...)

The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
1.9.6.1
-
RECOMMENDED NAME
GeneOntology No.
nitrate reductase (cytochrome)
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
2 ferrocytochrome + 2 H+ + nitrate = 2 ferricytochrome + nitrite
show the reaction diagram
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
oxidation
-
-
-
-
redox reaction
-
-
-
-
reduction
-
-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
nitrate reduction IV (dissimilatory)
-
-
Nitrogen metabolism
-
-
SYSTEMATIC NAME
IUBMB Comments
ferrocytochrome:nitrate oxidoreductase
-
CAS REGISTRY NUMBER
COMMENTARY hide
9029-42-9
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
strain H16
-
-
Manually annotated by BRENDA team
the genes for the periplasmic nitrate reductase are not part of the bacterial chromosome, but are located on the megaplasmid pHG1 present in the wild-type strain H16
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
nitrate + ferrocytochrome
nitrite + ferricytochrome + H2O
show the reaction diagram
nitrate + reduced acceptor
nitrite + acceptor
show the reaction diagram
nitrate + reduced acceptor
nitrite + oxidized acceptor
show the reaction diagram
-
-
-
-
?
nitrate + reduced benzyl viologen
nitrite + oxidized benzyl viologen
show the reaction diagram
-
-
-
?
nitrate + reduced benzyl viologen
nitrite + oxidized benzyl viologen + H2O
show the reaction diagram
nitrate + reduced methyl viologen
nitrite + oxidized methyl viologen
show the reaction diagram
-
-
-
-
?
nitrate + reduced methyl viologen
nitrite + oxidized methyl viologen + H2O
show the reaction diagram
nitrite + methyl viologen
nitrate + oxidized methyl viologen
show the reaction diagram
-
-
-
-
?
additional information
?
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
nitrate + ferrocytochrome
nitrite + ferricytochrome + H2O
show the reaction diagram
nitrate + reduced acceptor
nitrite + acceptor
show the reaction diagram
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4Fe-4S-center
bis(molybdopterin guanine dinucleotide)molybdenum cofactor
cytochrome
-
cytochrome c552
-
the enzyme is a complex of a 93000 Da polypeptide and a 16000 Da nitrate-oxidizable cytochrome c552, cytochrome c552 contains two c-type heme moieties
-
molybdenum cofactor
-
-
molybdopterin
additional information
-
enzyme contains no flavin
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Iron
-
contains iron
Mo5+
-
NapA contains a molybdo-bis(molybdopterin guanine dinucleotide) cofactor. The molybdenum ion coordination sphere of NapA includes two molybdopterin guanine dinucleotide dithiolenes, a protein-derived cysteinyl ligand and an oxygen atom. The Mo-O bond length is 2.6 A, which is indicative of a water ligand. In NapA or NapAB, the Mo5+ state can not be further reduced to Mo4+. A catalytic cycle for NapA is proposed in which nitrate binds to the Mo5+ ion and where a stable des-oxo Mo6+ species may participate
Mo6+
-
NapA contains a molybdo-bis(molybdopterin guanine dinucleotide) cofactor. The molybdenum ion coordination sphere of NapA includes two molybdopterin guanine dinucleotide dithiolenes, a protein-derived cysteinyl ligand and an oxygen atom. The Mo-O bond length is 2.6 A, which is indicative of a water ligand. In NapA or NapAB, the Mo5+ state can not be further reduced to Mo4+. A catalytic cycle for NapA is proposed in which nitrate binds to the Mo5+ ion and where a stable des-oxo Mo6+ species may participate
Molybdenum
-
molybdenum-containing enzyme, the nitrate molecule binds to the active site with the molabdenum ion in the +6 oxidation state, electron transfer to the active site occurs only in the proton-electron transfer stage, where the molybdenum-V species plays an important role in catalysis
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
azide
hydrogensulfite
-
0.1 mM, complete inhibition
p-chloromercuribenzoate
-
0.3 mM, completely inhibits, can be reversed by cysteine or glutathione
Sulfide
-
Na2S at 0.5 mM inactivates completely
Thiocyanate
-
competitive
additional information
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.045 - 0.12
nitrate
additional information
additional information
-
-
-
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.5
-
assay at
7 - 8.5
-
same rate between
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5.5 - 10
-
sharp drop of activity below pH 5.5 and above pH 10
7 - 9.5
-
pH 7.0: about 70% of maximal activity, pH 9.5: about 60% of maximal activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
-
assay at
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
mutant strain (M-6) overproduces the enzyme activity under anaerobic growth conditions
Manually annotated by BRENDA team
-
specific activity of the enzyme is higher in intact cells grown with butyrate than succinate as the sole source of carbon
Manually annotated by BRENDA team
-
specific activity of the enzyme is higher in intact cells grown with butyrate than succinate as the sole source of carbon
Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
92000
-
gel filtration
110000
-
gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dimer
-
1 * 93000 + 1 * 16000, SDS-PAGE
heterodimer
additional information
-
the nap operon of Escherichia coli K-12, encoding a periplasmic nitrate reductase, encodes seven proteins. The catalytic complex in the periplasm, NapA–NapB receives electrons from the quinol pool via the membrane-bound cytochrome NapC. Like NapA, B and C, NapD, is also essential for Nap activity. None of the remaining three polypeptides, NapF, G and H, which are predicted to encode non-heme, iron-sulfur proteins, are essential for Nap activity
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
proteolytic modification
P33937 and P0ABL3
the pre-NapA leader sequence is both unexpectedly long and, unless two successive proteolysis steps are involved, is cleaved at the unprecedented sequence G-Q-Q
additional information
-
NapF plays a role in the post-translational modification of NapA prior to the export of folded NapA via the twin-arginine translocation pathway into the periplasm
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
vapor diffusion method
-
sitting-drop vapour-diffusion method, crystals of the oxidized form of this enzyme are obtained using polyethylene glycol 3350 as precipitant. A single crystal diffracted to beyond 1.5 A at the ESRF (ID14-1), which is the highest resolution reported to date for a nitrate reductase. The unit-cell parameters are a = 142.2, b = 82.4, c = 96.8 A, beta = 100.7°, space group C2, and one heterodimer is present per asymmetric unit
-
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
50
-
10 min, stable
60
-
10 min, 10-15% loss of activity
70
-
5 min, complete and irreversible loss of activity
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
stable to prolonged dialysis
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
4°C, about 90% of the activity is lost after 48 h, no activity remains after 4 days
P33937 and P0ABL3
frozen, several months, stable
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
of NapA and NapB
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
-
P33937 and P0ABL3
expressed in Escherichia coli
-
structural genes, napA and napB, are cloned, and their nucleotide sequences is determined
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
NarL represses the expression of periplasmic nitrate reductase NapAB under anaerobiosis
-
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information