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Literature summary extracted from

  • Dilworth, M.J.; Fisher, K.; Kim, C.H.; Newton, W.E.
    Effects on substrate reduction of substitution of histidine-195 by glutamine in the alpha-subunit of the MoFe protein of Azotobacter vinelandii nitrogenase (1998), Biochemistry, 37, 17495-17505.
    View publication on PubMed

Protein Variants

EC Number Protein Variants Comment Organism
1.18.6.1 H195Q below 2% N2 reducing activity remaining compared to wild-type due to less effective N2 binding Azotobacter vinelandii

Inhibitors

EC Number Inhibitors Comment Organism Structure
1.18.6.1 N2 inhibits C2H2 reduction of mutant H195Q; maximal inhibition of H2 production at Fe protein to MoFe protein ration 2.5 Azotobacter vinelandii
1.18.6.1 N3- inhibits H2 production competitively and reversibly Azotobacter vinelandii

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
1.18.6.1 additional information
-
 additional information
-
 Azotobacter vinelandii

Metals/Ions

EC Number Metals/Ions Comment Organism Structure
1.18.6.1 Mg2+ Mg2+ required for MgATP complex Azotobacter vinelandii

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
1.18.6.1 8 reduced ferredoxin + 8 H+ + N2 + 16 ATP + 16 H2O Azotobacter vinelandii
-
 8 oxidized ferredoxin + H2 + 2 NH3 + 16 ADP + 16 phosphate
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
1.18.6.1 Azotobacter vinelandii
-
-
-

Purification (Commentary)

EC Number Purification (Comment) Organism
1.18.6.1 wild-type and mutant H195Q Azotobacter vinelandii

Reaction

EC Number Reaction Comment Organism Reaction ID
1.18.6.1 4 reduced ferredoxin + 8 H+ + N2 + 16 ATP + 16 H2O = 4 oxidized ferredoxin + H2 + 2 NH3 + 16 ADP + 16 phosphate enzyme is composed of 2 metalloproteins: component I MoFe protein and component II Fe protein Azotobacter vinelandii
a

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
1.18.6.1 additional information
-
 assay in anaerobic atmosphere required Azotobacter vinelandii
1.18.6.1 0.024
-
 purified mutant H195Q enzyme, anaerobic atmosphere Azotobacter vinelandii
1.18.6.1 0.7
-
 purified enzyme, anaerobic atmosphere Azotobacter vinelandii

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.18.6.1 8 reduced ferredoxin + 8 H+ + N2 + 16 ATP + 16 H2O
-
 Azotobacter vinelandii 8 oxidized ferredoxin + H2 + 2 NH3 + 16 ADP + 16 phosphate
-
 ?
1.18.6.1 reduced ferredoxin + H+ + ATP
-
 Azotobacter vinelandii oxidized ferredoxin + H2 + ADP + phosphate
-
 ?
1.18.6.1 reduced ferredoxin + H+ + N3- + ATP mutant H195Q shows only about 7.5% activity compared to wild-type Azotobacter vinelandii oxidized ferredoxin + NH3 + N2 + ADP + phosphate
-
 ?

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
1.18.6.1 additional information
-
-
 Azotobacter vinelandii

Temperature Range [°C]

EC Number Temperature Minimum [°C] Temperature Maximum [°C] Comment Organism
1.18.6.1 13 45
-
 Azotobacter vinelandii

Ki Value [mM]

EC Number Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
1.18.6.1 additional information
-
 additional information
-
 Azotobacter vinelandii