MetaCyc Enzyme: nitronate monooxygenase

Gene: 2-NPD Accession Number: G-9615 (MetaCyc)

Species: Cyberlindnera mrakii

Subunit composition of nitronate monooxygenase = [2-NPD]2
         nitronate monooxygenase subunit = 2-NPD

This enzyme was formerly referred to as 2-nitropropane dioxygenase (EC (reviewed in [Gadda09]).

Gene Citations: [Tchorzewski94]

Molecular Weight of Polypeptide: 41.467 kD (from nucleotide sequence)

Unification Links: Protein Model Portal:Q12723 , UniProt:Q12723

Relationship Links: Entrez-Nucleotide:PART-OF:U13900 , InterPro:IN-FAMILY:IPR004136 , InterPro:IN-FAMILY:IPR013785 , Pfam:IN-FAMILY:PF03060

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 27-Sep-2006 by Fulcher CA , SRI International
Revised 16-Dec-2009 by Fulcher CA , SRI International

Enzymatic reaction of: ethylnitronate monooxygenase

EC Number:

ethylnitronate + oxygen <=> acetaldehyde + nitrite + [unspecified degradation products]

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

Alternative Substrates for ethylnitronate: 3-nitro-2-pentanol [Kido76 ] , 2-nitropropane [Kido76 ]

In Pathways: alkylnitronates degradation

Nitronate monooxygenase (formerly 2-nitropropane dioxygenase, EC from Williopsis saturnus var. mrakii (Hansenula mrakii) catalyzes the oxygenative denitrification anionic nitroalkanes [Tchorzewski94, Kido76]. ethylnitronate is the anionic form of the neutral nitroalkane nitroethane (reviewed in [Gadda09]).

A Km value of 1.61 mM was determined for anionic 2-nitropropane. The enzyme was inhibited by superoxide dismutases from various species, cytochrome c, and NADH, reflecting the participation of superoxide in the reaction mechanism. This was confirmed by ESR spectroscopy. [Kido84].

Kinetic studies suggested evidence for an anion binding pocket in the enzyme that interacts with the nitro group of the substrate, providing key determinants for substrate binding and recognition. When ethylnitronate was used as substrate, the enzyme was competitively inhibited by the monovalent inorganic ions and aldehydes indicated here [Francis09].

Cofactors or Prosthetic Groups: FAD [Kido76]

Inhibitors (Competitive): pentanal [Francis09] , hexanal [Francis09] , propanal [Francis09] , butanal [Francis09] , nitrate [Francis09] , iodide [Francis09] , chloride [Francis09] , bromide [Francis09] , nitrite [Francis09] , fluoride [Francis09]

Inhibitors (Noncompetitive): nitromethane [Kido76]

Inhibitors (Unknown Mechanism): (R)-adrenaline [Kido84] , NADH [Kido84] , L-dithiothreitol [Kido84] , glutathione [Kido84] , nitroblue tetrazolium [Kido84] , NADPH [Kido78] , tiron [Kido78] , catechol [Kido78] , pyrogallol [Kido78] , phloroglucinol [Kido78] , 1-naphthol [Kido78] , serotonin [Kido78] , 5-hydroxy-L-tryptophan [Kido78] , resorcinol [Kido78] , benzene-1,4-diol [Kido78] , 1,2,4-benzenetriol [Kido78] , 2-naphthol [Kido78] , thiophenol [Kido78] , L-cysteine [Kido76] , p-chloromercuribenzoate [Kido76] , N-ethylmaleimide [Kido76] , iodoacetate [Kido76] , sulfite [Kido76]


Francis09: Francis K, Gadda G (2009). "Kinetic evidence for an anion binding pocket in the active site of nitronate monooxygenase." Bioorg Chem 37(5);167-72. PMID: 19683782

Gadda09: Gadda G, Francis K (2009). "Nitronate monooxygenase, a model for anionic flavin semiquinone intermediates in oxidative catalysis." Arch Biochem Biophys. PMID: 19577534

Kido76: Kido T, Soda K, Suzuki T, Asada K (1976). "A new oxygenase, 2-nitropropane dioxygenase of Hansenula mrakii. Enzymologic and spectrophotometric properties." J Biol Chem 251(22);6994-7000. PMID: 11214

Kido78: Kido T, Soda K (1978). "Properties of 2-nitropropane dioxygenase of Hansenula mrakii. Formation and participation of superoxide." J Biol Chem 253(1);226-32. PMID: 201619

Kido84: Kido T, Soda K (1984). "Oxidation of anionic nitroalkanes by flavoenzymes, and participation of superoxide anion in the catalysis." Arch Biochem Biophys 234(2);468-75. PMID: 6149727

Tchorzewski94: Tchorzewski M, Kurihara T, Esaki N, Soda K (1994). "Unique primary structure of 2-nitropropane dioxygenase from Hansenula mrakii." Eur J Biochem 226(3);841-6. PMID: 7813473

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Sat Oct 10, 2015, biocyc13.