Information on EC 1.9.6.1 - nitrate reductase (cytochrome):
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The lowest common taxonomy group for this enzyme is: Proteobacteria

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EC NUMBERCOMMENTARY
1.9.6.1-

RECOMMENDED NAMEGeneOntology No.
nitrate reductase (cytochrome)GO:0050140

REACTIONREACTION DIAGRAMCOMMENTARYORGANISM UNIPROT ACCESSION NO.LITERATURE
2 ferrocytochrome + 2 H+ + nitrate = 2 ferricytochrome + nitrite
show the reaction diagram		----

REACTION TYPEORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
oxidation----
redox reaction----
reduction----

PATHWAYKEGG LinkMetaCyc Link
nitrate reduction IV (dissimilatory)-PWY-5674

SYSTEMATIC NAMEIUBMB Comments
ferrocytochrome:nitrate oxidoreductase-

SYNONYMSORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
NAPParacoccus pantotrophus--696375, 696917
NAPCupriavidus necator--696375, 698544
NAPEscherichia coli, Paracoccus denitrificans--696375
NAPShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi--712967
NAP enzymeCampylobacter jejuni--654561
Nap-alphaShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella loihica, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-isoform712967
NAP-betaShewanella amazonensis, Shewanella baltica, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-isoform712967
NapAEscherichia coli--674891
NapAEscherichia coli-catalytic subunit of the periplasmic nitrate reductase system675847
NapAEscherichia coli K-12P33937 and P0ABL3-697968
NapADesulfovibrio desulfuricans--699015
NapABParacoccus pantotrophus--684990
NapABRalstonia eutropha H16--695337
NapABPseudomonas aeruginosa--711653
NapABCParacoccus pantotrophus--698636
NapDAGHBShewanella amazonensis, Shewanella baltica, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-isoform712967
NapEDABCShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella loihica, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-isoform712967
nitrate reductase, periplasmicCupriavidus necator--698544
periplasmic nitrate reductaseCampylobacter jejuni--654561
periplasmic nitrate reductaseEscherichia coli K-12--696082, 700256
periplasmic nitrate reductaseParacoccus pantotrophus--696917, 697696, 698636
periplasmic nitrate reductaseDesulfovibrio desulfuricans--699199
periplasmic nitrate reductasePseudomonas aeruginosa--711653
periplasmic nitrate reductaseShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi--712967
periplasmic nitrate reductasesCupriavidus necator, Escherichia coli, Paracoccus denitrificans, Paracoccus pantotrophus--696375
reductase, nitrate (cytochrome)----
respiratory nitrate reductase----
benzyl viologen-nitrate reductase----
additional informationAliivibrio fischeri-the enzymes EC 1.7.99.4 and EC 1.9.6.1 are probably identical, in vivo cytochrome serves as electron donor in the electron transport chain to nitrate395176

CAS REGISTRY NUMBERCOMMENTARY
9029-42-9-

ORGANISMCOMMENTARYLITERATURESEQUENCE CODESEQUENCE DB SOURCE
Aliivibrio fischeri-395176--Manually annotated by BRENDA team
Campylobacter jejuni-654561--Manually annotated by BRENDA team
Cupriavidus necator-696375--Manually annotated by BRENDA team
Cupriavidus necatorstrain H16698544--Manually annotated by BRENDA team
Desulfovibrio desulfuricans-699015, 699199--Manually annotated by BRENDA team
Escherichia coli-674891, 675847, 696375, 698555--Manually annotated by BRENDA team
Escherichia coli K-12-395185, 696082, 700256--Manually annotated by BRENDA team
Escherichia coli K-12P33937: napA, P0ABL3: napB697968P33937 and P0ABL3SwissProtManually annotated by BRENDA team
Paracoccus denitrificans-696375, 697965--Manually annotated by BRENDA team
Paracoccus pantotrophus-684990, 696375, 698636--Manually annotated by BRENDA team
Paracoccus pantotrophus-696917Q56350UniProtManually annotated by BRENDA team
Paracoccus pantotrophusmutant strain M6697696--Manually annotated by BRENDA team
Pseudomonas aeruginosa-711653--Manually annotated by BRENDA team
Ralstonia eutropha H16the 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 H16695337--Manually annotated by BRENDA team
Shewanella amazonensis-712967--Manually annotated by BRENDA team
Shewanella baltica-712967--Manually annotated by BRENDA team
Shewanella baltica OS155-712967--Manually annotated by BRENDA team
Shewanella baltica OS185-712967--Manually annotated by BRENDA team
Shewanella baltica OS195-712967--Manually annotated by BRENDA team
Shewanella baltica OS223-712967--Manually annotated by BRENDA team
Shewanella denitrificans-712967--Manually annotated by BRENDA team
Shewanella frigidimarina-712967--Manually annotated by BRENDA team
Shewanella halifaxensis-712967--Manually annotated by BRENDA team
Shewanella loihica-712967--Manually annotated by BRENDA team
Shewanella oneidensis-712967--Manually annotated by BRENDA team
Shewanella pealeana-712967--Manually annotated by BRENDA team
Shewanella piezotolerans-712967--Manually annotated by BRENDA team
Shewanella putrefaciens-712967--Manually annotated by BRENDA team
Shewanella putrefaciens CN-32-712967--Manually annotated by BRENDA team
Shewanella sediminis-712967--Manually annotated by BRENDA team
Shewanella sp.-712967--Manually annotated by BRENDA team
Shewanella sp. MR-4-712967--Manually annotated by BRENDA team
Shewanella sp. MR-7-712967--Manually annotated by BRENDA team
Shewanella sp. W3-18-1-712967--Manually annotated by BRENDA team
Shewanella woodyi-712967--Manually annotated by BRENDA team

GENERAL INFORMATIONORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
physiological functionParacoccus pantotrophusQ56350the Nap-deficient mutant KD102 shows increased diauxic lag when switched from aerobic to anoxic respiration, suggesting Nap is responsible for shorter lags and helps in adaptation to anoxic metabolism after transition from aerobic conditions696917
physiological functionPseudomonas aeruginosa-napAB expression is required for anaerobic growth recovery by DELTAnarXL (a deletion encompassing the bulk of narXL)711653

SUBSTRATEPRODUCT                      REACTION DIAGRAMORGANISM UNIPROT ACCESSION NO. COMMENTARY/
Substrate		 LITERATURE/
Substrate		 COMMENTARY/
Product		 LITERATURE/
Product		 Reversibility
r=reversible
ir=irreversible
?=not specified
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Pseudomonas aeruginosa--711653--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-NapG and H, but not NapF, are essential for electron transfer from ubiquinol to NapAB. NapC is essential for electron transfer from both ubiquinol and menaquinol to NapAB. It is proposed that NapG and H form an energy conserving quinol dehydrogenase functioning as either components of a proton pump or in a Q cycle, as electrons are transferred from ubiquinol to the membrane-bound cytochrome NapC700256--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-periplasmic nitrate reductase is expressed under nitrate-limiting conditions. NapG and NapH form a quinol dehydrogenase that couples electron transfer from the high midpoint redox potential ubiquinone-ubiquinol couple via cytochrome NapC and NapB to NapA696082--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli-the periplasmic cytochrome c-linked nitrate reductase is encoded by the napFDAGHBC operon. The napF operon apparently encodes a low-substrate-induced reductase that is maximally expressed only at low levels of nitrate. Expression is suppressed under high-nitrate conditions. In contrast, the narGHJI operon is only weakly expressed at low nitrate levels but is maximally expressed when nitrate is elevated. The narGHJI operon is therefore a high-substrate-induced operon that somehow provides a second and distinct role in nitrate metabolism by the cell. Nitrite, the end product of each enzyme, has only a minor effect on the expression of either operon. Finally, nitrate, but not nitrite, is essential for repression of napF gene expression. These studies reveal that nitrate rather than nitrite is the primary signal that controls the expression of these two nitrate reductase operons in a differential and complementary fashion698555--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-NapG and NapH form a quinol dehydrogenase that couples electron transfer from the high midpoint redox potential ubiquinone–ubiquinol couple via cytochrome NapC and NapB to NapA696082--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-the membrane-bound cytochrome NapC is essential for electron transfer from both ubiquinol and menaquinol to NapAB700256--?
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Shewanella sp., Shewanella putrefaciens, Shewanella oneidensis, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella pealeana, Shewanella piezotolerans, Shewanella sediminis, Shewanella woodyi, Shewanella denitrificans, Shewanella amazonensis, Shewanella baltica-the reduction of nitrate catalysed by NAP takes place in the 90 kDa NapA subunit712967--?
nitrate + reduced acceptornitrite + acceptor
show the reaction diagram		Aliivibrio fischeri-reduced benzyl viologen as electron donor, reduced methyl viologen as electron donor395176-395176?
nitrate + reduced acceptornitrite + acceptor
show the reaction diagram		Aliivibrio fischeri-the enzymes EC 1.7.99.4 and EC 1.9.6.1 are probably identical, in vivo cytochrome serves as electron donor in the electron transport chain to nitrate, electron transport chain in vivo: Fe3 + via specific cytochrome-nitrate reductase to NO3-395176--?
nitrate + reduced acceptornitrite + oxidized acceptor
show the reaction diagram		Desulfovibrio desulfuricans--699015, 699199--?
nitrate + reduced benzyl viologennitrite + oxidized benzyl viologen
show the reaction diagram		Paracoccus pantotrophusQ56350-696917--?
nitrate + reduced benzyl viologennitrite + oxidized benzyl viologen + H2O
show the reaction diagram		Cupriavidus necator--698544--?
nitrate + reduced benzyl viologennitrite + oxidized benzyl viologen + H2O
show the reaction diagram		Escherichia coli K-12--395185--?
nitrate + reduced methyl viologennitrite + oxidized methyl viologen
show the reaction diagram		Paracoccus pantotrophus--698636--?
nitrate + reduced methyl viologennitrite + oxidized methyl viologen + H2O
show the reaction diagram		Paracoccus denitrificans--697965--?
nitrate + reduced methyl viologennitrite + oxidized methyl viologen + H2O
show the reaction diagram		Escherichia coli K-12--395185, 696082--?
nitrate + reduced methyl viologennitrite + oxidized methyl viologen + H2O
show the reaction diagram		Paracoccus pantotrophus--684990--?
nitrate + reduced methyl viologennitrite + oxidized methyl viologen + H2O
show the reaction diagram		Paracoccus pantotrophus-very high substrate specificity. The enzyme does not reduce any other oxocompound (chlorate, bromate, iodate, nitrite, molybdate, sulphate, thiosulphate, tetrathionate, selenate, dimethyl sulphoxide, trimethylamine-A-oxide, borate and arsenate)697696--?
nitrite + methyl viologennitrate + oxidized methyl viologen
show the reaction diagram		Pseudomonas aeruginosa--711653--?
additional information?-Aliivibrio fischeri-the enzymes EC 1.7.99.4 and EC 1.9.6.1 are probably identical, in vivo cytochrome serves as electron donor in the electron transport chain to nitrate395176---
additional information?-Cupriavidus necator-an insertion in the napA gene leads to a complete loss of enzyme activity but does not abolish the ability of Alcaligenes eutrophus to use nitrate as a nitrogen source or as an electron acceptor in anaerobic respiration. Nevertheless, the NAP-deficient mutant shows delayed growth after transition from aerobic to anaerobic respiration, suggesting a role for periplasmic nitrate reductase in the adaptation to anaerobic metabolism698544---
additional information?-Escherichia coli K-12-NapABC enzyme is responsible for nitrate dissimilation. Periplasmic nitrate reductase (NapABC enzyme) can function in anaerobic respiration but does not constitute a site for generating proton motive force. napF-lacZ is expressed preferentially at relatively low nitrate concentrations in continuous cultures. This finding support the hypothesis that NapABC enzyme may function in Escherichia coli when low nitrate concentrations limit the bioenergetic efficiency of nitrate respiration via NarGHI enzyme395185---
additional information?-Campylobacter jejuni-the nap operon encodes the only nitrate reductase in Campylobacter jejuni and that it is essential in mediating growth using nitrate as a terminal electron acceptor under oxygen-limited conditions654561---
additional information?-Paracoccus pantotrophus-NapAB catalysed nitrate reduction driven by direct electron transfer from the electrode to NapAB, protein film voltammetry. Exploration of the nitrate reductase activity of purified NapAB as a function of electrochemical potential, substrate concentration and pH using protein film voltammetry. Nitrate reduction by NapAB occurs at potentials below approx. 0.1 V at pH 7. These are lower potentials than required for NarGH nitrate reduction. The potentials required for Nap nitrate reduction are also likely to require ubiquinol/ubiquinone ratios higher than are needed to activate the H+-pumping oxidases expressed during aerobic growth where Nap levels are maximal. Thus the operational potentials of Paracoccus pantotrophus NapAB are consistent with a productive role in redox balancing684990---

NATURAL SUBSTRATESNATURAL PRODUCTSREACTION DIAGRAMORGANISM UNIPROT ACCESSION NO.COMMENTARY SUBSTRATELITERATURE
(Substrate)		COMMENTARY PRODUCTLITERATURE
(Product)
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Pseudomonas aeruginosa--711653--
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-NapG and H, but not NapF, are essential for electron transfer from ubiquinol to NapAB. NapC is essential for electron transfer from both ubiquinol and menaquinol to NapAB. It is proposed that NapG and H form an energy conserving quinol dehydrogenase functioning as either components of a proton pump or in a Q cycle, as electrons are transferred from ubiquinol to the membrane-bound cytochrome NapC700256--
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli K-12-periplasmic nitrate reductase is expressed under nitrate-limiting conditions. NapG and NapH form a quinol dehydrogenase that couples electron transfer from the high midpoint redox potential ubiquinone-ubiquinol couple via cytochrome NapC and NapB to NapA696082--
nitrate + ferrocytochromenitrite + ferricytochrome + H2O
show the reaction diagram		Escherichia coli-the periplasmic cytochrome c-linked nitrate reductase is encoded by the napFDAGHBC operon. The napF operon apparently encodes a low-substrate-induced reductase that is maximally expressed only at low levels of nitrate. Expression is suppressed under high-nitrate conditions. In contrast, the narGHJI operon is only weakly expressed at low nitrate levels but is maximally expressed when nitrate is elevated. The narGHJI operon is therefore a high-substrate-induced operon that somehow provides a second and distinct role in nitrate metabolism by the cell. Nitrite, the end product of each enzyme, has only a minor effect on the expression of either operon. Finally, nitrate, but not nitrite, is essential for repression of napF gene expression. These studies reveal that nitrate rather than nitrite is the primary signal that controls the expression of these two nitrate reductase operons in a differential and complementary fashion698555--
nitrate + reduced acceptornitrite + acceptor
show the reaction diagram		Aliivibrio fischeri-the enzymes EC 1.7.99.4 and EC 1.9.6.1 are probably identical, in vivo cytochrome serves as electron donor in the electron transport chain to nitrate, electron transport chain in vivo: Fe3 + via specific cytochrome-nitrate reductase to NO3-395176--
additional information?-Cupriavidus necator-an insertion in the napA gene leads to a complete loss of enzyme activity but does not abolish the ability of Alcaligenes eutrophus to use nitrate as a nitrogen source or as an electron acceptor in anaerobic respiration. Nevertheless, the NAP-deficient mutant shows delayed growth after transition from aerobic to anaerobic respiration, suggesting a role for periplasmic nitrate reductase in the adaptation to anaerobic metabolism698544--
additional information?-Escherichia coli K-12-NapABC enzyme is responsible for nitrate dissimilation. Periplasmic nitrate reductase (NapABC enzyme) can function in anaerobic respiration but does not constitute a site for generating proton motive force. napF-lacZ is expressed preferentially at relatively low nitrate concentrations in continuous cultures. This finding support the hypothesis that NapABC enzyme may function in Escherichia coli when low nitrate concentrations limit the bioenergetic efficiency of nitrate respiration via NarGHI enzyme395185--
additional information?-Campylobacter jejuni-the nap operon encodes the only nitrate reductase in Campylobacter jejuni and that it is essential in mediating growth using nitrate as a terminal electron acceptor under oxygen-limited conditions654561--

COFACTORORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATUREIMAGE
4Fe-4S-centerShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-the 90 kDa NapA subunit contains a one [4Fe-4S] iron-sulfur cluster712967 2D-image
bis-molybdopterin guanine dinucleotideCampylobacter jejuni-subunit NapA is an 90000 Da catalytic subunit which binds a bis-molybdenum guanosine dinucleoside cofactor and a [4Fe4S] cluster654561-
bis-molybdopterin guanine dinucleotideEscherichia coli-NapA contains a molybdo-bis(molybdopterin guanine dinucleotide) cofactor674891-
cytochromeAliivibrio fischeri-presence of a bound cytochrome395176-
cytochromeEscherichia coli K-12-NapG and NapH form a quinol dehydrogenase that couples electron transfer from the high midpoint redox potential ubiquinone-ubiquinol couple via cytochrome NapC and NapB to NapA696082-
cytochromeEscherichia coli K-12-the membrane-bound cytochrome NapC is essential for electron transfer from both ubiquinol and menaquinol to NapAB700256-
cytochrome c552Paracoccus pantotrophus-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 moieties697696-
hemeEscherichia coli-the NapA holoenzyme associates with a di-heme c-type cytochrome redox partner (NapB)674891 2D-image
hemeParacoccus pantotrophus-contains 1.3 mol heme per mol of protein (assuminga 110-kDa molecular mass)697696 2D-image
hemeEscherichia coli K-12P33937 and P0ABL3subunit NapB is a diheme cytochrome c697968 2D-image
molybdenum cofactorDesulfovibrio desulfuricans--699015 2D-image
MolybdopterinShewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi-the 90 kDa NapA subunit contains a Mo-bis-molybdopterin guanine dinucleotide cofactor712967 2D-image
additional informationAliivibrio fischeri-enzyme contains no flavin395176-

METALS and IONS ORGANISM UNIPROT ACCESSION NO.COMMENTARY LITERATURE
FeCampylobacter jejuni-subunit NapA is an 90000 Da catalytic subunit which binds a bis-molybdenum guanosine dinucleoside cofactor and a [4Fe4S] cluster654561
FeEscherichia coli-NapA contains a [4Fe-4S] cluster674891
FeParacoccus pantotrophus-contains 2.7 mol iron (of which 1.4 mol is presumably non-haem iron) per mol of protein (assuming a 110000 Da molecular mass)697696
IronAliivibrio fischeri-contains iron395176
MoCampylobacter jejuni-subunit NapA is an 90000 Da catalytic subunit which binds a bis-molybdenum guanosine dinucleoside cofactor and a [4Fe4S] cluster654561
MoParacoccus pantotrophus-contains molybdenum, 0.9 mol molybdenum: 1 mol protein (assuminga 110000 Da molecular mass)697696
MoEscherichia coli K-12P33937 and P0ABL3molybdoprotein697968
Mo5+Escherichia coli-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 participate674891
Mo6+Escherichia coli-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 participate674891
MolybdenumDesulfovibrio desulfuricans-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 catalysis699199

INHIBITORSORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
azideAliivibrio fischeri-NaN3 at 30 mM completely inactivates395176 2D-image
azideParacoccus pantotrophus-mixed type inhibition684990 2D-image
p-chloromercuribenzoateAliivibrio fischeri-0.3 mM, completely inhibits, can be reversed by cysteine or glutathione395176 2D-image
SulfideAliivibrio fischeri-Na2S at 0.5 mM inactivates completely395176 2D-image
ThiocyanateParacoccus pantotrophus-competitive684990 2D-image
hydrogensulfiteAliivibrio fischeri-0.1 mM, complete inhibition395176 2D-image
additional informationParacoccus pantotrophus-insensitive to inhibition by azide697696-
additional informationParacoccus denitrificans-insensitive to azide697965-
additional informationPseudomonas aeruginosa-NapAB activity is azide-resistant711653-

ACTIVATING COMPOUNDORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
No entries in this field

KM VALUE [mM]KM VALUE [mM] MaximumSUBSTRATEORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
0.045-nitrateParacoccus pantotrophus-pH 7, NapAB catalysed nitrate reduction driven by direct electron transfer from the electrode to NapAB, protein film voltammetry684990 2D-image
0.12-nitrateCupriavidus necator-pH 5.5, 37°C698544 2D-image
additional information-additional informationAliivibrio fischeri--395176-

TURNOVER NUMBER [1/s] TURNOVER NUMBER MAXIMUM[1/s] SUBSTRATEORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
No entries in this field

kcat/KM VALUE [1/mMs-1]kcat/KM VALUE [1/mMs-1] MaximumSUBSTRATEORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
No entries in this field

Ki VALUE [mM]Ki VALUE [mM] MaximumINHIBITORORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
No entries in this field

IC50 VALUE [mM]IC50 VALUE [mM] MaximumINHIBITORORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE IMAGE
No entries in this field

SPECIFIC ACTIVITY [µmol/min/mg] SPECIFIC ACTIVITY MAXIMUM ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
1.484-Aliivibrio fischeri--395176
95-Paracoccus pantotrophus--697696

pH OPTIMUMpH MAXIMUMORGANISM UNIPROT ACCESSION NO. COMMENTARYLITERATURE
5.5-Cupriavidus necator-assay at698544
78.5Aliivibrio fischeri-same rate between395176
7.38Paracoccus pantotrophus--697696

pH RANGEpH RANGE MAXIMUMORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
5.510Aliivibrio fischeri-sharp drop of activity below pH 5.5 and above pH 10395176
79.5Paracoccus pantotrophus-pH 7.0: about 70% of maximal activity, pH 9.5: about 60% of maximal activity697696

TEMPERATURE OPTIMUMTEMPERATURE OPTIMUM MAXIMUMORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
24-Paracoccus pantotrophus-assay at697696
37-Cupriavidus necator-assay at698544

TEMPERATURE RANGE TEMPERATURE MAXIMUM ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
No entries in this field

pI VALUEpI VALUE MAXIMUMORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
No entries in this field

SOURCE TISSUE ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE SOURCE
culture condition:anaerobically-grown cellParacoccus pantotrophus-mutant strain (M-6) overproduces the enzyme activity under anaerobic growth conditions697696Manually annotated by BRENDA team
culture condition:butyrate-grown cellParacoccus denitrificans-specific activity of the enzyme is higher in intact cells grown with butyrate than succinate as the sole source of carbon697965Manually annotated by BRENDA team
culture condition:succinate-grown cellParacoccus denitrificans-specific activity of the enzyme is higher in intact cells grown with butyrate than succinate as the sole source of carbon697965Manually annotated by BRENDA team

LOCALIZATION ORGANISM UNIPROT ACCESSION NO. COMMENTARY GeneOntology No. LITERATURE SOURCE
periplasmEscherichia coli K-12---395185, 696082, 697968, 700256Manually annotated by BRENDA team
periplasmCampylobacter jejuni---654561Manually annotated by BRENDA team
periplasmEscherichia coli---674891, 675847, 698555Manually annotated by BRENDA team
periplasmRalstonia eutropha H16---695337Manually annotated by BRENDA team
periplasmParacoccus pantotrophus---696917, 697696, 698636Manually annotated by BRENDA team
periplasmParacoccus denitrificans---697965Manually annotated by BRENDA team
periplasmCupriavidus necator---698544Manually annotated by BRENDA team
periplasmDesulfovibrio desulfuricans---699199Manually annotated by BRENDA team
periplasmPseudomonas aeruginosa---711653Manually annotated by BRENDA team
solubleAliivibrio fischeri---395176Manually annotated by BRENDA team

PDBSCOPCATHORGANISM
3ml1, downloadSCOP (3ml1)CATH (3ml1)Cupriavidus necator (strain ATCC 17699 / H16 / DSM 428 / Stanier 337)
3o5a, downloadSCOP (3o5a)CATH (3o5a)Cupriavidus necator (strain ATCC 17699 / H16 / DSM 428 / Stanier 337)

MOLECULAR WEIGHT MOLECULAR WEIGHT MAXIMUM ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
92000-Cupriavidus necator-gel filtration698544
100000-Aliivibrio fischeri--395176
110000-Paracoccus pantotrophus-gel filtration697696

SUBUNITS ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
?Campylobacter jejuni-x * 90000 + x * 16000, two-subunit complex, NapA is an 90000 Da catalytic subunit which binds a bis-molybdenum guanosine dinucleoside cofactor and a [4Fe4S] cluster. NapB is an 16000 Da electron-transfer subunit, which in other bacteria binds two c-type haems654561
?Escherichia coli-1 * 17000 (NapB) + 1 * 90000 (NapA), the NapA holoenzyme associates with a di-heme c-type cytochrome redox partner (NapB). NapA and NapB proteins purify independently and not as a tight heterodimeric complex. Dissociation constants of 0.015 mM and 0.032 mM are determined for oxidized and reduced NapAB complexes, respectively674891
?Paracoccus pantotrophus-x * 16000 + x * 90000, SDS-PAGE684990
dimerParacoccus pantotrophus-1 * 93000 + 1 * 16000, SDS-PAGE697696
heterodimerEscherichia coli K-12P33937 and P0ABL31 * 90000 (NapA) + 1 * 16000 (NapB), Nap activity is lost rapidly during the separation of NapA from NapB by anion exchange chromatography, SDS-PAGE697968
heterodimerCupriavidus necator-1 * 17000 + 1 * 87000, SDS-PAGE; 1 * 93309 + 1 * 18924, calculated from sequence698544
additional informationEscherichia coli K-12-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 activity700256

POSTTRANSLATIONAL MODIFICATION ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
proteolytic modificationEscherichia coli K-12P33937 and P0ABL3the pre-NapA leader sequence is both unexpectedly long and, unless two successive proteolysis steps are involved, is cleaved at the unprecedented sequence G-Q-Q697968
additional informationEscherichia coli-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 periplasm675847

Crystallization/COMMENTARY ORGANISM UNIPROT ACCESSION NO. LITERATURE
vapor diffusion methodEscherichia coli-674891
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 unitRalstonia eutropha H16-695337

pH STABILITYpH STABILITY MAXIMUM ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
No entries in this field

TEMPERATURE STABILITYTEMPERATURE STABILITY MAXIMUM ORGANISM UNIPROT ACCESSION NO. COMMENTARYLITERATURE
50-Aliivibrio fischeri-10 min, stable395176
60-Aliivibrio fischeri-10 min, 10-15% loss of activity395176
70-Aliivibrio fischeri-5 min, complete and irreversible loss of activity395176

GENERAL STABILITYORGANISM UNIPROT ACCESSION NO.LITERATURE
stable to prolonged dialysisAliivibrio fischeri-395176

ORGANIC SOLVENT ORGANISM UNIPROT ACCESSION NO. COMMENTARY LITERATURE
No entries in this field

OXIDATION STABILITY ORGANISM UNIPROT ACCESSION NO. LITERATURE
No entries in this field

STORAGE STABILITY ORGANISM UNIPROT ACCESSION NO. LITERATURE
frozen, several months, stableAliivibrio fischeri-395176
4°C, about 90% of the activity is lost after 48 h, no activity remains after 4 daysEscherichia coli K-12P33937 and P0ABL3697968

Purification/COMMENTARY ORGANISM UNIPROT ACCESSION NO. LITERATURE
-Aliivibrio fischeri-395176
-Cupriavidus necator-698544
of NapA and NapBEscherichia coli-674891
-Paracoccus pantotrophus-684990, 697696
-Ralstonia eutropha H16-695337

Cloned/COMMENTARY ORGANISM UNIPROT ACCESSION NO. LITERATURE
structural genes, napA and napB, are cloned, and their nucleotide sequences is determinedCupriavidus necator-698544
-Escherichia coli K-12P33937 and P0ABL3697968
expressed in Escherichia coliParacoccus pantotrophus-698636

EXPRESSION ORGANISM UNIPROT ACCESSION NO. LITERATURE
NarL represses the expression of periplasmic nitrate reductase NapAB under anaerobiosisPseudomonas aeruginosa-711653

ENGINEERINGORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
additional informationCupriavidus necator-the physiological role of NAP in nitrate metabolism is investigated in studies with a mutant bearing a transposon insertion in one of the structural genes698544

Renatured/COMMENTARYORGANISM UNIPROT ACCESSION NO.LITERATURE
No entries in this field

APPLICATIONORGANISM UNIPROT ACCESSION NO.COMMENTARYLITERATURE
No entries in this field

REF. AUTHORS TITLE JOURNAL VOL. PAGES YEAR ORGANISMLINK TO PUBMEDSOURCE
395176Sadana, J.C.; McElroy, W.D.Nitrate reductase from Achromobacter fischeri. Purification and properties: Function of flavines and cytochromeArch. Biochem. Biophys.6716-341957Aliivibrio fischeri PubMed
395185Steward, V.; Lu, Y.; Darwin, A.J.Periplasmic nitrate reductase (NapABC enzyme) supports anaerobic respiration by Escherichia coli K-12J. Bacteriol.1841314-13232002Escherichia coli K-12 PubMed
654561Pittman, M.S.; Kelly, D.J.Electron transport through nitrate and nitrite reductases in Campylobacter jejuniBiochem. Soc. Trans.33190-1922005Campylobacter jejuni PubMed
674891Jepson, B.J.; Mohan, S.; Clarke, T.A.; Gates, A.J.; Cole, J.A.; Butler, C.S.; Butt, J.N.; Hemmings, A.M.; Richardson, D.J.Spectropotentiometric and structural analysis of the periplasmic nitrate reductase from Escherichia coliJ. Biol. Chem.2826425-64372006Escherichia coli PubMed
675847Nilavongse, A.; Brondijk, T.H.; Overton, T.W.; Richardson, D.J.; Leach, E.R.; Cole, J.A.The NapF protein of the Escherichia coli periplasmic nitrate reductase system: demonstration of a cytoplasmic location and interaction with the catalytic subunit, NapAMicrobiology1523227-32372006Escherichia coli PubMed
684990Gates, A.J.; Richardson, D.J.; Butt, J.N.Voltammetric characterization of the aerobic energy-dissipating nitrate reductase of Paracoccus pantotrophus: exploring the activity of a redox-balancing enzyme as a function of electrochemical potentialBiochem. J.409159-1682008Paracoccus pantotrophus PubMed
695337Coelho, C.; Gonzalez, P.J.; Trincao, J.; Carvalho, A.L.; Najmudin, S.; Hettman, T.; Dieckman, S.; Moura, J.J.; Moura, I.; Romao, M.J.Heterodimeric nitrate reductase (NapAB) from Cupriavidus necator H16: purification, crystallization and preliminary X-ray analysisActa Crystallogr. Sect. F63516-5192007Ralstonia eutropha H16 PubMed
696082Brondijk, T.H.; Nilavongse, A.; Filenko, N.; Richardson, D.J.; Cole, J.A.NapGH components of the periplasmic nitrate reductase of Escherichia coli K-12: location, topology and physiological roles in quinol oxidation and redox balancingBiochem. J.37947-552004Escherichia coli K-12 PubMed
696375Berks, B.C.; Ferguson, S.J.; Moir, J.W.; Richardson, D.J.Enzymes and associated electron transport systems that catalyse the respiratory reduction of nitrogen oxides and oxyanions.Biochim. Biophys. Acta123297-1731995Cupriavidus necator, Escherichia coli, Paracoccus denitrificans, Paracoccus pantotrophus PubMed
696917Durvasula, K.; Jantama, K.; Fischer, K.; Vega, A.; Koopman, B.; Svoronos, S.A.Effect of periplasmic nitrate reductase on diauxic lag of Paracoccus pantotrophusBiotechnol. Prog.25973-9792009Paracoccus pantotrophus PubMed
697696Berks, B.C.; Richardson, D.J.; Robinson, C.; Reilly, A.; Aplin, R.T.; Ferguson, S.J.Purification and characterization of the periplasmic nitrate reductase from Thiosphaera pantotrophaEur. J. Biochem.220117-1241994Paracoccus pantotrophus PubMed
697965Sears, H.J.; Ferguson, S.J.; Richardson, D.J.; Spiro, S.The identification of a periplasmic nitrate reductase in Paracoccus denitrificansFEMS MIcrobiol. Lett.113107-1121993Paracoccus denitrificans-
697968Thomas, G.; Potter, L.; Cole, J.A.The periplasmic nitrate reductase from Escherichia coli: a heterodimeric molybdoprotein with a double-arginine signal sequence and an unusual leader peptide cleavage siteFEMS Microbiol. Lett.174167-1711999Escherichia coli K-12 PubMed
698544Siddiqui, R.A.; Warnecke-Eberz, U.; Hengsberger, A.; Schneider, B.; Kostka, S.; Friedrich, B.Structure and function of a periplasmic nitrate reductase in Alcaligenes eutrophus H16J. Bacteriol.1755867-58761993Cupriavidus necator PubMed
698555Wang, H.; Tseng, C.P.; Gunsalus, R.P.The napF and narG nitrate reductase operons in Escherichia coli are differentially expressed in response to submicromolar concentrations of nitrate but not nitriteJ. Bacteriol.1815303-53081999Escherichia coli PubMed
698636Stewart, V.; Bledsoe, P.J.; Chen, L.L.; Cai, A.Catabolite repression control of napF (periplasmic nitrate reductase) operon expression in Escherichia coli K-12J. Bacteriol.191996-10052009Paracoccus pantotrophus PubMed
699015Hofmann, M.Density functional theory study of model complexes for the revised nitrate reductase active site in Desulfovibrio desulfuricans NapAJ. Biol. Inorg. Chem.141023-10352009Desulfovibrio desulfuricans PubMed
699199Cerqueira, N.M.; Gonzalez, P.J.; Brondino, C.D.; Romao, M.J.; Romao, C.C.; Moura, I.; Moura, J.J.The effect of the sixth sulfur ligand in the catalytic mechanism of periplasmic nitrate reductaseJ. Comput. Chem.302466-24842009Desulfovibrio desulfuricans PubMed
700256Brondijk, T.H.; Fiegen, D.; Richardson, D.J.; Cole, J.A.Roles of NapF, NapG and NapH, subunits of the Escherichia coli periplasmic nitrate reductase, in ubiquinol oxidationMol. Microbiol.44245-2552002Escherichia coli K-12 PubMed
711653Van Alst, N.E.; Sherrill, L.A.; Iglewski, B.H.; Haidaris, C.G.Compensatory periplasmic nitrate reductase activity supports anaerobic growth of Pseudomonas aeruginosa PAO1 in the absence of membrane nitrate reductaseCan. J. Microbiol.551133-11442009Pseudomonas aeruginosa PubMed
712967Simpson, P.J.; Richardson, D.J.; Codd, R.The periplasmic nitrate reductase in Shewanella: the resolution, distribution and functional implications of two NAP isoforms, NapEDABC and NapDAGHBMicrobiology156302-3122010Shewanella amazonensis, Shewanella baltica, Shewanella denitrificans, Shewanella frigidimarina, Shewanella halifaxensis, Shewanella loihica, Shewanella oneidensis, Shewanella pealeana, Shewanella piezotolerans, Shewanella putrefaciens, Shewanella sediminis, Shewanella sp., Shewanella woodyi PubMed

LINKS TO OTHER DATABASES (specific for EC-Number 1.9.6.1)
ExplorEnz
ExPASy
KEGG
MetaCyc
NCBI: PubMed, Protein, Nucleotide, Structure, Genome, OMIM
IUBMB Enzyme Nomenclature
PROSITE Database of protein families and domains
SYSTERS
Protein Mutant Database
InterPro (database of protein families, domains and functional sites)