IUBMB Enzyme Nomenclature


Accepted name: nitronate monooxygenase

Reaction: ethylnitronate + O2 = acetaldehyde + nitrite + other products

Other name(s): NMO; 2-nitropropane dioxygenase (incorrect)

Systematic name: nitronate:oxygen 2-oxidoreductase (nitrite-forming)

Comments: Previously classified as 2-nitropropane dioxygenase (EC, but it is now recognized that this was the result of the slow ionization of nitroalkanes to their nitronate (anionic) forms. The enzymes from the fungus Neurospora crassa and the yeast Williopsis saturnus var. mrakii (formerly classified as Hansenula mrakii) contain non-covalently bound FMN as the cofactor. Neither hydrogen peroxide nor superoxide were detected during enzyme turnover. Active towards linear alkyl nitronates of lengths between 2 and 6 carbon atoms and, with lower activity, towards propyl-2-nitronate. The enzyme from N. crassa can also utilize neutral nitroalkanes, but with lower activity.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Francis, K., Russell, B. and Gadda, G. Involvement of a flavosemiquinone in the enzymatic oxidation of nitroalkanes catalyzed by 2-nitropropane dioxygenase. J. Biol. Chem. 280 (2005) 5195-5204. [PMID: 15582992]

2. Ha, J.Y., Min, J.Y., Lee, S.K., Kim, H.S., Kim do, J., Kim, K.H., Lee, H.H., Kim, H.K., Yoon, H.J. and Suh, S.W. Crystal structure of 2-nitropropane dioxygenase complexed with FMN and substrate. Identification of the catalytic base. J. Biol. Chem. 281 (2006) 18660-18667. [PMID: 16682407]

3. Gadda, G. and Francis, K. Nitronate monooxygenase, a model for anionic flavin semiquinone intermediates in oxidative catalysis. Arch. Biochem. Biophys. 493 (2010) 53-61. [PMID: 19577534]

4. Francis, K. and Gadda, G. Kinetic evidence for an anion binding pocket in the active site of nitronate monooxygenase. Bioorg. Chem. 37 (2009) 167-172. [PMID: 19683782]

[EC created 1984 as EC, transferred 2009 to EC, modified 2011]

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