| EC |
1.18.6.1 |
| Accepted name: |
nitrogenase |
| Reaction: |
8 reduced ferredoxin + 8 H+ + N2 + 16 ATP + 16 H2O = 8 oxidized ferredoxin + H2 + 2 NH3 + 16 ADP + 16 phosphate |
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For diagram of reaction, click here |
| Other name(s): |
reduced ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing) |
| Systematic name: |
ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing, molybdenum-dependent) |
| Comments: |
Requires Mg2+. The enzyme is a complex of two components (namely dinitrogen reductase 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: |
BRENDA, EAWAG-BBD, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 9013-04-1 |
| References: |
| 1. |
Zumft, W.G., Paneque, A., Aparicio, P.J. and Losada, M. Mechanism of nitrate reduction in Chlorella. Biochem. Biophys. Res. Commun. 36 (1969) 980–986. [DOI] [PMID: 4390523] |
| 2. |
Liang, J. and Burris, R.H. Hydrogen burst associated with nitrogenase-catalyzed reactions. Proc. Natl. Acad. Sci. USA 85 (1988) 9446–9450. [DOI] [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 (2004) 11852–11863. [DOI] [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 (2000) 7221–7228. [DOI] [PMID: 10852721] |
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| [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] |
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