EC - Vanadium-dependent nitrogenase

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IntEnz Enzyme Nomenclature


Accepted name:
vanadium-dependent nitrogenase
Other names:
vnfD (gene name)
vnfG (gene name)
vnfK (gene name)
Systematic name:
ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing, vanadium-dependent)




Requires Mg2+. This enzyme, originally isolated from the bacterium Azotobacter vinelandii, is a complex of two components (namely dinitrogen reductase and dinitrogenase). Dinitrogen reductase is a [4Fe-4S] protein, which, in the presence of ATP, transfers an electron from ferredoxin to the dinitrogenase component. Dinitrogenase is a vanadium-iron protein that reduces dinitrogen to two molecules of ammonia in three successive two-electron reductions via diazine and hydrazine. Compared with molybdenum-depedent nitrogenase (EC, this enzyme produces more dihydrogen and consumes more ATP per dinitrogen molecule being reduced. Unlike EC, this enzyme can also use CO as substrate, producing ethylene, ethane and propane [7,9].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Eady, R. R., Richardson, T. H., Miller, R. W., Hawkins, M., Lowe, D. J.
    The vanadium nitrogenase of Azotobacter chroococcum. Purification and properties of the Fe protein.
    Biochem. J. 256 : 189-196 (1988). [PMID: 2851977]
  2. Miller, R. W., Eady, R. R.
    Molybdenum and vanadium nitrogenases of Azotobacter chroococcum. Low temperature favours N2 reduction by vanadium nitrogenase.
    Biochem. J. 256 : 429-432 (1988). [PMID: 3223922]
  3. Thorneley, R. N., Bergstrom, N. H., Eady, R. R., Lowe, D. J.
    Vanadium nitrogenase of Azotobacter chroococcum. MgATP-dependent electron transfer within the protein complex.
    Biochem. J. 257 : 789-794 (1989). [PMID: 2784670]
  4. Dilworth, M. J., Eldridge, M. E., Eady, R. R.
    Correction for creatine interference with the direct indophenol measurement of NH3 in steady-state nitrogenase assays.
    Anal. Biochem. 207 : 6-10 (1992). [PMID: 1336937]
  5. Dilworth, M. J., Eldridge, M. E., Eady, R. R.
    The molybdenum and vanadium nitrogenases of Azotobacter chroococcum: effect of elevated temperature on N2 reduction.
    Biochem. J. 289 : 395-400 (1993). [PMID: 8424785]
  6. Eady, R.R.
    Current status of structure function relationships of vanadium nitrogenase.
    Coordinat. Chem. Rev. 237 : 23-30 (2003).
  7. Lee, C. C., Hu, Y., Ribbe, M. W.
    Vanadium nitrogenase reduces CO.
    Science 329 : 642 (2010). [PMID: 20689010]
  8. Lee, C. C., Hu, Y., Ribbe, M. W.
    Tracing the hydrogen source of hydrocarbons formed by vanadium nitrogenase.
    Angew. Chem. Int. Ed. Engl. 50 : 5545-5547 (2011). [PMID: 21538750]
  9. Sippel, D., Einsle, O.
    The structure of vanadium nitrogenase reveals an unusual bridging ligand.
    Nat. Chem. Biol. 13 : 956-960 (2017). [PMID: 28692069]

[EC created 2018]