IntEnz

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EC 1.18.6.1 - Nitrogenase

IntEnz Enzyme Nomenclature
EC 1.18.6.1

Names

Reaction

• 21448 [IUBMB]
  16

  ATP

  ATP

  Name origin: UniProt - CHECKED (C)

  CHEBI:30616

  Formula: C10H12N5O13P3
  Charge: -4

  ChEBI compound status: CHECKED (C)

  

  +

  16

  H₂O

  H2O

  Name origin: UniProt - CHECKED (C)

  CHEBI:15377

  Formula: H2O
  Charge: 0

  ChEBI compound status: CHECKED (C)

  

  +

  N₂

  N2

  Name origin: UniProt - CHECKED (C)

  CHEBI:17997

  Formula: N2
  Charge: 0

  ChEBI compound status: CHECKED (C)

  

  +

  8

  reduced [2Fe-2S]-[ferredoxin]

  reduced [2Fe-2S]-[ferredoxin]

  GENERIC:10001

  Is ROOT: no
  ROOT compound: GENERIC:9997

  Number of residues: 1

  [2Fe-2S]1+ [2Fe-2S](1+) Name origin: UniProt - CHECKED (C) CHEBI:33738 Formula: Fe2S2 Charge: 1 Position: undefined ChEBI compound status: CHECKED (C)

  =

  16

  ADP

  ADP

  Name origin: UniProt - CHECKED (C)

  CHEBI:456216

  Formula: C10H12N5O10P2
  Charge: -3

  ChEBI compound status: CHECKED (C)

  

  +

  6

  H⁺

  H(+)

  Name origin: UniProt - CHECKED (C)

  CHEBI:15378

  Formula: H
  Charge: 1

  ChEBI compound status: CHECKED (C)

  

  +

  H₂

  H2

  Name origin: UniProt - CHECKED (C)

  CHEBI:18276

  Formula: H2
  Charge: 0

  ChEBI compound status: CHECKED (C)

  

  +

  2

  NH₄⁺

  NH4(+)

  Name origin: UniProt - CHECKED (C)

  CHEBI:28938

  Formula: H4N
  Charge: 1

  ChEBI compound status: CHECKED (C)

  

  +

  8

  oxidized [2Fe-2S]-[ferredoxin]

  oxidized [2Fe-2S]-[ferredoxin]

  GENERIC:10000

  Is ROOT: no
  ROOT compound: GENERIC:9997

  Number of residues: 1

  [2Fe-2S]2+ [2Fe-2S](2+) Name origin: UniProt - CHECKED (C) CHEBI:33737 Formula: Fe2S2 Charge: 2 Position: undefined ChEBI compound status: CHECKED (C)

  +

  16

  phosphate

  phosphate

  Name origin: UniProt - CHECKED (C)

  CHEBI:43474

  Formula: HO4P
  Charge: -2

  ChEBI compound status: CHECKED (C)

  

Cofactors

• iron-sulfur
• vanadium cation or Mo cation

Comments:

Requires Mg²⁺. The enzyme is a complex of two components (namely dinitrogen reducatse and dinitrogenase). Dinitrogen reductase is a [4Fe-4S] protein, which, in the presence of two molecules of ATP, transfers an electron from ferredoxin to the dinitrogenase component. Dinitrogenase is a molybdenum-iron protein that reduces dinitrogen to two molecules of ammonia in three successive two-electron reductions via diazene and hydrazine. The reduction is initiated by formation of hydrogen in stoichiometric amounts [2]. Acetylene is reduced to ethylene (but only very slowly to ethane), azide to nitrogen and ammonia, and cyanide to methane and ammonia. In the absence of a suitable substrate, hydrogen is slowly formed. Ferredoxin may be replaced by flavodoxin [see EC 1.19.6.1 nitrogenase (flavodoxin)]. The enzyme does not reduce CO (cf. EC 1.18.6.2, vanadium-dependent nitrogenase).

Links to other databases

References

1. Zumft, W.G., Paneque, A., Aparicio, P.J. and Losada, M.
   Mechanism of nitrate reduction in Chlorella.
   Biochem. Biophys. Res. Commun. 36: 980-986 (1969). [PMID: 4390523]
2. Liang, J. and Burris, R.H.
   Hydrogen burst associated with nitrogenase-catalyzed reactions.
   Proc. Natl. Acad. Sci. USA 85: 9446-9450 (1989). [PMID: 3200830]
3. Dance, I.
   The mechanism of nitrogenase. Computed details of the site and geometry of binding of alkyne and alkene substrates and intermediates.
   J. Am. Chem. Soc. 126: 11852-11863 (2004). [PMID: 15382920]
4. Chan, J.M., Wu, W., Dean, D.R. and Seefeldt, L.C.
   Construction and characterization of a heterodimeric iron protein: defining roles for adenosine triphosphate in nitrogenase catalysis.
   Biochemistry 39: 7221-7228 (2000). [PMID: 10852721]

[EC 1.18.6.1 created 1978 as EC 1.18.2.1, transferred 1984 to EC 1.18.6.1, modified 2005, modified 2018]