ENZYME entry: EC 1.18.6.1

Accepted Name
Nitrogenase.
Reaction catalysed
8 reduced ferredoxin + 8 H(+) + N(2) + 16 ATP + 16 H(2)O <=> 8 oxidized ferredoxin + H(2) + 2 NH(3) + 16 ADP + 16 phosphate
Cofactor(s)
Iron-sulfur; Vanadium or molybdenum.
Comment(s)
  • Composed of two proteins that can be separated but are both required for nitrogenase activity.
  • Dinitrogen reductase is a [4Fe-4S] protein, which, with two molecules of ATP and ferredoxin, generates an electron.
  • The electron is transferred to the other protein, dinitrogenase (molybdoferredoxin).
  • Dinitrogenase is a molybdenum-iron protein that reduces dinitrogen in three succesive two-electron reductions from nitrogen to diimine to hydrazine to two molecules of ammonia; the molybdenum may be replaced by vanadium or iron.
  • The reduction is initiated by formation of hydrogen in stoichiometric amounts.
  • 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).
  • Formerly EC 1.18.2.1.
Cross-references
PROSITEPDOC00085 ; PDOC00580
BRENDA1.18.6.1
EC2PDB1.18.6.1
ExplorEnz1.18.6.1
PRIAM enzyme-specific profiles1.18.6.1
KEGG Ligand Database for Enzyme Nomenclature1.18.6.1
IUBMB Enzyme Nomenclature1.18.6.1
IntEnz1.18.6.1
MEDLINEFind literature relating to 1.18.6.1
MetaCyc1.18.6.1
UniProtKB/Swiss-Prot
P16266, ANFD_AZOVI;  Q46082, ANFD_CLOHU;  O68955, ANFD_HELGE;  
Q07933, ANFD_RHOCA;  O68946, ANFG_AZOMA;  O68943, ANFG_AZOPA;  
P16268, ANFG_AZOVI;  Q46083, ANFG_CLOHU;  Q46244, ANFG_CLOPA;  
Q07934, ANFG_RHOCA;  O68940, ANFG_RHORU;  P16267, ANFK_AZOVI;  
Q46084, ANFK_CLOHU;  Q07935, ANFK_RHOCA;  Q44045, NIFD_ALCFA;  
P33177, NIFD_ANASL;  P25313, NIFD_AZOBR;  P07328, NIFD_AZOVI;  
P06121, NIFD_BRAJA;  P06120, NIFD_BRASP;  P00467, NIFD_CLOPA;  
O07642, NIFD_CYAA5;  Q55029, NIFD_CYAP8;  Q02452, NIFD_FRAAL;  
P77874, NIFD_HERSE;  P00466, NIFD_KLEPN;  P55170, NIFD_METBA;  
P51605, NIFD_METIV;  P0CW50, NIFD_METMI;  P0CW51, NIFD_METMP;  
O27605, NIFD_METTH;  P20620, NIFD_METTL;  Q50788, NIFD_METTM;  
P52337, NIFD_NOSCO;  P00464, NIFD_NOSS1;  Q00239, NIFD_PLEBO;  
P06769, NIFD_RHICP;  P00465, NIFD_RHILT;  P19066, NIFD_RHISN;  
P08717, NIFD_RHOCA;  P06662, NIFD_THIFE;  P0A3S1, NIFH1_ANAVT;  
P26251, NIFH1_AZOC5;  P26248, NIFH1_AZOCH;  P00459, NIFH1_AZOVI;  
P00456, NIFH1_CLOPA;  Q47917, NIFH1_MASLA;  P54799, NIFH1_METBA;  
P51602, NIFH1_METIV;  O27602, NIFH1_METTH;  P25767, NIFH1_METTL;  
Q50785, NIFH1_METTM;  P00457, NIFH1_NOSS1;  Q9AKT8, NIFH1_PAEDU;  
P0CY95, NIFH1_RHOCA;  D5ANI3, NIFH1_RHOCB;  Q44484, NIFH2_ANAVT;  
P26252, NIFH2_AZOC5;  P06118, NIFH2_AZOCH;  P15335, NIFH2_AZOVI;  
P09552, NIFH2_CLOPA;  Q47921, NIFH2_MASLA;  P54800, NIFH2_METBA;  
P08624, NIFH2_METIV;  O26739, NIFH2_METTH;  P08625, NIFH2_METTL;  
O30577, NIFH2_NOSS1;  Q9AKT4, NIFH2_PAEDU;  Q07942, NIFH2_RHOCA;  
P16269, NIFH3_AZOVI;  P09553, NIFH3_CLOPA;  P22548, NIFH4_CLOPA;  
P09554, NIFH5_CLOPA;  P09555, NIFH6_CLOPA;  B7JA99, NIFH_ACIF2;  
B5ER76, NIFH_ACIF5;  Q44044, NIFH_ALCFA;  A6TTY3, NIFH_ALKMQ;  
P33178, NIFH_ANASL;  P17303, NIFH_AZOBR;  B6YRI6, NIFH_AZOPC;  
P06117, NIFH_BRAJA;  P00463, NIFH_BRASP;  Q3AR70, NIFH_CHLCH;  
B3EH88, NIFH_CHLL2;  B3QQ12, NIFH_CHLP8;  B3EL81, NIFH_CHLPB;  
A1BEH0, NIFH_CHLPD;  Q8KC92, NIFH_CHLTE;  Q97ME5, NIFH_CLOAB;  
Q59270, NIFH_CLOCB;  O07641, NIFH_CYAA5;  B8HWE3, NIFH_CYAP4;  
B7KG76, NIFH_CYAP7;  Q55028, NIFH_CYAP8;  Q47G67, NIFH_DECAR;  
Q3Z7C7, NIFH_DEHE1;  B8FAC4, NIFH_DESAA;  C6BX34, NIFH_DESAD;  
C0QKK8, NIFH_DESAH;  B1I0Y8, NIFH_DESAP;  P71156, NIFH_DESGI;  
C4XRK2, NIFH_DESMR;  A4J8C2, NIFH_DESRM;  P26249, NIFH_ENTAG;  
Q6D2Y8, NIFH_ERWCT;  P08925, NIFH_FRAAL;  Q2J4F8, NIFH_FRASC;  
Q47922, NIFH_FRASE;  A8L2C4, NIFH_FRASN;  P46034, NIFH_FRASP;  
Q9ZIE4, NIFH_GLUDA;  P77873, NIFH_HERSE;  B5XPH2, NIFH_KLEP3;  
P00458, NIFH_KLEPN;  A0L6X0, NIFH_MAGSM;  Q2FUB7, NIFH_METHJ;  
Q58289, NIFH_METJA;  Q8PYY0, NIFH_METMA;  P0CW56, NIFH_METMI;  
A3CWW3, NIFH_METMJ;  P0CW57, NIFH_METMP;  B8ITG7, NIFH_METNO;  
B0UAK2, NIFH_METS4;  P06119, NIFH_METVO;  P26250, NIFH_NOSCO;  
Q09158, NIFH_NOSMU;  Q51296, NIFH_NOSS6;  P52336, NIFH_NOSSN;  
Q3B2P6, NIFH_PELLD;  B4SC59, NIFH_PELPB;  Q00240, NIFH_PLEBO;  
B4S9H5, NIFH_PROA2;  A4SFU6, NIFH_PROVI;  A4VJ70, NIFH_PSEU5;  
P00462, NIFH_RHIET;  P20623, NIFH_RHILE;  Q98AP7, NIFH_RHILO;  
P00461, NIFH_RHILT;  P00460, NIFH_RHIME;  P19068, NIFH_RHISN;  
Q2J1I1, NIFH_RHOP2;  Q13C78, NIFH_RHOPS;  P22921, NIFH_RHORU;  
A3PLS9, NIFH_RHOS1;  Q3J0H1, NIFH_RHOS4;  O31183, NIFH_RHOSH;  
A7NR80, NIFH_ROSCS;  A5USK5, NIFH_ROSS1;  A0LH11, NIFH_SYNFM;  
Q2JTL7, NIFH_SYNJA;  Q2JP78, NIFH_SYNJB;  C5BTB0, NIFH_TERTT;  
P06661, NIFH_THIFE;  C4LAS5, NIFH_TOLAT;  P0A3S2, NIFH_TRIAZ;  
O34106, NIFH_TRIEI;  P26254, NIFH_TRITH;  Q0W443, NIFH_UNCMA;  
Q7M8U8, NIFH_WOLSU;  Q5NLG3, NIFH_ZYMMO;  P25314, NIFK_AZOBR;  
P07329, NIFK_AZOVI;  P20621, NIFK_BRAJA;  P06122, NIFK_BRASP;  
P11347, NIFK_CLOPA;  O07643, NIFK_CYAA5;  Q55030, NIFK_CYAP8;  
Q57118, NIFK_FRAAL;  P77875, NIFK_HERSE;  P09772, NIFK_KLEPN;  
P51754, NIFK_METBA;  P0CW52, NIFK_METMI;  P0CW53, NIFK_METMP;  
O27606, NIFK_METTH;  P20622, NIFK_METTL;  P95296, NIFK_METTM;  
P00468, NIFK_NOSS1;  P19067, NIFK_RHISN;  P15052, NIFK_THIFE;  
P15332, VNFD_AZOCH;  O68953, VNFD_AZOPA;  O68954, VNFD_AZOSA;  
P16855, VNFD_AZOVI;  P15333, VNFG_AZOCH;  O68951, VNFG_AZOSA;  
P16857, VNFG_AZOVI;  Q57302, VNFK_ANAVT;  P15334, VNFK_AZOCH;  
O68949, VNFK_AZOPA;  O68952, VNFK_AZOSA;  P16856, VNFK_AZOVI;  

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