Nitrate Reductase Enzyme

A Nitrate Reductase Enzyme is an enzyme that catalyzes NAD(P)H reduction of Nitrate To Nitrite.

• AKA: Nitrate Reductase.
• Context:
  • It is composed of Polypeptide and one each of FAD, Heme-Iron, and Molybdenum-Molybdopterin.
  • It can serve Plants, Algae, and Fungi as a central point for integration of Metabolism by governing flux of reduced Nitrogen by several regulatory mechanisms.
• Example(s):
  • Periplasmic Nitrate Reductase.
    • in Thiosphaera Pantotropha http://www.uniprot.org/uniprot/Q56350
    • in Pseudomonas sp. http://www.uniprot.org/uniprot/P97235
  • PMID 7639719: “The napEDABC locus coding for the periplasmic nitrate reductase of Thiosphaera pantotropha has been cloned and sequenced ”
• Counter-Example(s):
  • PMID 10217771: “Yet the role of periplasmic nitrate reductase in denitrification has not been clearly defined. To analyze the function of the periplasmic nitrate reductase in Pseudomonas sp. strain G-179, the nap gene cluster was identified and found to be linked to genes involved in reduction of nitrite and nitric oxide and anaerobic heme biosynthesis.”
• See: Algae, Fingi.

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References

2009

• (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Nitrate_reductase
  • Nitrate reductase enzymes are a group of enzymes that reduce nitrate to nitrite.
  • Nitrate reductase (1)- is a large and complex enzyme with multiple subunits and a mass of ~800 kDa. It contains bound FAD, Mo, and cytochrome 557, and has ferredoxin Fe4S4 center. It is NADH/NADPH-dependent according to organism. Mo is bound to a cofactor containing a pteridine ring to form molybdopterin.
  • Nitrite reductase (2, 3, 4) catalyzes the last three steps in the reduction of nitrate to NH3. It contains one ferredoxin Fe2S2 center and one molecule of siroheme (partially-reduced Fe porphyrin) and the electron donor for each step is ferredoxin.
  • Bacteria can be differentiated based on whether they have nitrate reductases. (See Nitrate reductase test.)
• Gene Ontologyhttp://amigo.geneontology.org/cgi-bin/amigo/term-details.cgi?term=GO:0009703&session_id=5828amigo1240506945
  • Accession: GO:0009703
  • Ontology: molecular function
  • Synonyms
    • exact: assimilatory NADH: nitrate reductase activity
    • exact: assimilatory NADH:nitrate reductase activity
    • exact: NADH-dependent nitrate reductase activity
    • exact: NADH-nitrate reductase activity
    • exact: NADH:nitrate oxidoreductase activity
    • exact: NADH:nitrate reductase activity
    • exact: nitrate reductase (NADH(2)) activity
    • exact: nitrate reductase (NADH2)
    • exact: nitrite:NAD+ oxidoreductase activity
    • broad: assimilatory nitrate reductase activity
  • Definition
    • Catalysis of the reaction: NO2- (nitrite) + NAD+ + H2O = NO3- (nitrate) + NADH + H+. [source: EC:1.7.1.1]----