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Literature summary for 1.18.6.1 extracted from

  • Kim, C.H.; Newton, W.E.; Dean, D.R.
    Role of the MoFe protein alpha-subunit histidine-195 residue in FeMo-cofactor binding and nitrogenase catalysis (1995), Biochemistry, 34, 2798-2808.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
H195G alpha-His of MoFe protein, site directed mutagenesis, reduced MoFe protein activity, slightly decreased Fe protein activity, altered phenotype Azotobacter vinelandii
H195L alpha-His of MoFe protein, site directed mutagenesis, reduced MoFe protein activity, increased Fe protein activity, altered phenotype Azotobacter vinelandii
H195N alpha-His of MoFe protein, site directed mutagenesis, reduced MoFe protein activity, altered phenotype Azotobacter vinelandii
H195Q alpha-His of MoFe protein, site directed mutagenesis, decreased MoFe protein activity, altered phenotype Azotobacter vinelandii
H195T alpha-His of MoFe protein, site directed mutagenesis, reduced MoFe protein and Fe protein activity, altered phenotype Azotobacter vinelandii
H195Y alpha-His of MoFe protein, site directed mutagenesis, reduced MoFe protein and Fe protein activity, altered phenotype Azotobacter vinelandii

Inhibitors

Inhibitors Comment Organism Structure
CO inhibition of H+ reduction by about 50% Azotobacter vinelandii
N2 inhibits the C2H2 reduction Azotobacter vinelandii

KM Value [mM]

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

Metals/Ions

Metals/Ions Comment Organism Structure
additional information structure and organization of metal clusters Azotobacter vinelandii

Organism

Organism UniProt Comment Textmining
Azotobacter vinelandii
-
-
-

Purification (Commentary)

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

Reaction

Reaction Comment Organism Reaction ID
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

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
wild-type and diverse alpha-His195 MoFe protein mutants Azotobacter vinelandii
additional information
-
assay in anaerobic atmosphere required Azotobacter vinelandii
0.066
-
crude extract, 100% Ar atmosphere, H2 production Azotobacter vinelandii

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 reduced ferredoxin + 2 H+ + acetylene + 2 ATP + 2 H2O anaerobic atmosphere Azotobacter vinelandii 2 oxidized ferredoxin + ethylene + 2 ADP + 2 phosphate reduction cycle continues until complete reduction of the substrate to ethane ?
8 reduced ferredoxin + 8 H+ + N2 + 16 ATP + 16 H2O
-
Azotobacter vinelandii 8 oxidized ferredoxin + H2 + 2 NH3 + 16 ADP + 16 phosphate
-
?
reduced ferredoxin + H+ + ATP
-
Azotobacter vinelandii oxidized ferredoxin + H2 + ADP + phosphate
-
?

Cofactor

Cofactor Comment Organism Structure
additional information structure of MoFe-cofactor Azotobacter vinelandii

Ki Value [mM]

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