|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 22.214.171.124) (reviewed in [Gadda09]).
Gene Citations: [Tchorzewski94]
Molecular Weight of Polypeptide: 41.467 kD (from nucleotide sequence)
Enzymatic reaction of: ethylnitronate monooxygenase
EC Number: 126.96.36.199
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
The reaction is physiologically favored in the direction shown.
In Pathways: alkylnitronates degradation
Nitronate monooxygenase (formerly 2-nitropropane dioxygenase, EC 188.8.131.52) 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].
Inhibitors (Competitive): pentanal [Francis09] , hexanal [Francis09] , propanal [Francis09] , butanal [Francis09] , nitrate [Francis09] , iodide [Francis09] , chloride [Francis09] , bromide [Francis09] , nitrite [Francis09] , fluoride [Francis09]
Inhibitors (Unknown Mechanism): (R)-adrenaline [Kido84] , NADH [Kido84] , 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]
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
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