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EC 1.18.6.1 Details
show Brenda entryEC number
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
Other name(s)
reduced ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing)
Systematic name
ferredoxin:dinitrogen oxidoreductase (ATP-hydrolysing, molybdenum-dependent)
CAS registry number
9013-04-1
Comment
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).
History
created 1978 as EC 1.18.2.1, transferred 1984 to EC 1.18.6.1, modified 2005, modified 2018
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1 Oxidoreductases
1.1.1.70 created 1965, deleted 1978 1.1.1.74 created 1972, deleted 1976 1.1.1.89 created 1972, deleted 1976 1.1.1.109 created 1972, deleted 1976 1.1.1.139 created 1972, deleted 1978 1.1.1.155 created 1976, deleted 2004 1.1.1.171 created 1978, deleted 1984 1.1.1.180 created 1983, deleted 1984 1.1.1.182 created 1983, deleted 1990 1.1.1.204 created 1972 as EC 1.2.1.37, transferred 1984 to EC 1.1.1.204, modified 1989, deleted 2004 1.1.1.242 created 1992, deleted 2001 1.1.1.253 created 1999, deleted 2003
1.1.2 With a cytochrome as acceptor
