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Literature summary for extracted from

  • Tachiki, T.; Nason, A.
    Preparation and proterties of apoenzyme of nitrate reductases from wild-type and nit-3 mutant of Neurospora crassa (1983), Biochim. Biophys. Acta, 744, 16-22.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
additional information enzyme can be reactivated by molybdenum and dithioerythritol Neurospora crassa

Protein Variants

Protein Variants Comment Organism
additional information nit-1 mutant: lacks all activities except FAD-dependent NADPH:cytochrome c reductase activity,nit-2 mutant: reduced FAD:- and reduced methyl viologen:nitrate reductase activities but lacks the other two activities Neurospora crassa


Metals/Ions Comment Organism Structure
Molybdenum 1 mol per mol enzyme protein, activation of enzyme after urea treatment, little stimulation Neurospora crassa

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
2 * 97000: nit-3 enzyme, 2 * 132000, wild-type Neurospora crassa
nit-3 enzyme, gel filtration Neurospora crassa
wild-type, gel filtration Neurospora crassa

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
nitrate + NADPH Neurospora crassa first step in nitrate assimilation nitrite + NADP+ + H2O


Organism UniProt Comment Textmining
Neurospora crassa
wild-type STA4, nit-1 and nit-3 mutants

Purification (Commentary)

Purification (Comment) Organism
partially purification of wild-type and nit-3 mutant by streptomycin sulfate precipitation and ammonium sulfate fractionation, of nit-1 mutant by protamine sulfate fractionation, ammonium sulfate precipitation and gel filtration Neurospora crassa

Source Tissue

Source Tissue Comment Organism Textmining
Neurospora crassa

Storage Stability

Storage Stability Organism
5Ā°C, urea-treated, 0.1 M potassium phosphate buffer, pH 7.3, 5 mM EDTA, 2 mM dithioerythritol, 0.5 mg/ml or more bovine serum albumin, stable for 18 h without loss of activity Neurospora crassa

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
nitrate + NADPH 4 activities: NADPH-nitrate reductase, FADH-nitrate reductase, reduced methyl viologen-nitrate reductase and NADPH-cytochrome c reductase Neurospora crassa nitrite + NADP+ + H2O
nitrate + NADPH first step in nitrate assimilation Neurospora crassa nitrite + NADP+ + H2O


Subunits Comment Organism
dimer 2 * 97000: nit-3 enzyme, 2 * 132000, wild-type Neurospora crassa
More nit-1 mutant enzyme is the apoprotein of nitrate reductase Neurospora crassa
More aggregate of two different polypeptide chains: one responsible for transport of electrons fom NADPH to FAD or cytochrome c, nit-1 enzyme. The other transfers electrons from FAD via molybdenum to nitrate, nit-3 enzyme Neurospora crassa


Cofactor Comment Organism Structure
cytochrome b557
Neurospora crassa
heme 2 mol heme iron per mol enzyme protein Neurospora crassa