EC 1.5.3.5     
Accepted name: (S)-6-hydroxynicotine oxidase
Reaction: (S)-6-hydroxynicotine + H2O + O2 = 1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one + H2O2 (overall reaction)
(1a) (S)-6-hydroxynicotine + O2 = 5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol + H2O2
(1b) 5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol + H2O = 1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one (spontaneous)
Glossary: (S)-6-hydroxynicotine = 5-[(2S)-1-methylpyrrolidin-2-yl]pyridin-2-ol
1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one = 6-hydroxypseudooxynicotine
5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol = 6-hydroxy-N-methylmyosmine
Other name(s): L-6-hydroxynicotine oxidase; 6-hydroxy-L-nicotine oxidase; 6-hydroxy-L-nicotine:oxygen oxidoreductase; nctB (gene name)
Systematic name: (S)-6-hydroxynicotine:oxygen oxidoreductase
Comments: A flavoprotein (FAD). The enzyme, which participates in nicotine degradation, is specific for the (S) isomer of 6-hydroxynicotine. The bacterium Arthrobacter nicotinovorans, in which this enzyme was originally discovered, has a different enzyme that catalyses a similar reaction with the less common (R)-isomer (cf. EC 1.5.3.6, (R)-6-hydroxynicotine oxidase).
References:
1.  Decker, K. and Bleeg, H. Induction and purification of stereospecific nicotine oxidizing enzymes from Arthrobacter oxidans. Biochim. Biophys. Acta 105 (1965) 313–324. [PMID: 5849820]
2.  Dai, V.D., Decker, K. and Sund, H. Purification and properties of L-6-hydroxynicotine oxidase. Eur. J. Biochem. 4 (1968) 95–102. [PMID: 5646150]
3.  Schenk, S., Hoelz, A., Krauss, B. and Decker, K. Gene structures and properties of enzymes of the plasmid-encoded nicotine catabolism of Arthrobacter nicotinovorans. J. Mol. Biol. 284 (1998) 1323–1339. [PMID: 9878353]
4.  Qiu, J., Wei, Y., Ma, Y., Wen, R., Wen, Y. and Liu, W. A novel (S)-6-hydroxynicotine oxidase gene from Shinella sp. strain HZN7. Appl. Environ. Microbiol. 80 (2014) 5552–5560. [PMID: 25002425]
[EC 1.5.3.5 created 1972, modified 2015]
 
 
EC 1.5.3.6     
Accepted name: (R)-6-hydroxynicotine oxidase
Reaction: (R)-6-hydroxynicotine + H2O + O2 = 1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one + H2O2 (overall reaction)
(1a) (R)-6-hydroxynicotine + O2 = 5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol + H2O2
(1b) 5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol + H2O = 1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one (spontaneous)
Glossary: (R)-6-hydroxynicotine = 5-[(2R)-1-methylpyrrolidin-2-yl]pyridin-2-ol
5-(N-methyl-4,5-dihydro-1H-pyrrol-2-yl)pyridin-2-ol = 6-hydroxy-N-methylmyosmine
1-(6-hydroxypyridin-3-yl)-4-(methylamino)butan-1-one = 6-hydroxypseudooxynicotine
Other name(s): D-6-hydroxynicotine oxidase; 6-hydroxy-D-nicotine oxidase
Systematic name: (R)-6-hydroxynicotine:oxygen oxidoreductase
Comments: A flavoprotein (FAD). The enzyme, which participates in nicotine degradation, is specific for (R) isomer of 6-hydroxynicotine, derived from the uncommon (R)-nicotine. The bacterium Arthrobacter nicotinovorans, in which this enzyme was originally discovered, has a different enzyme that catalyses a similar reaction with the (S)-isomer (cf. EC 1.5.3.5, (S)-6-hydroxynicotine oxidase).
References:
1.  Decker, K. and Bleeg, H. Induction and purification of stereospecific nicotine oxidizing enzymes from Arthrobacter oxidans. Biochim. Biophys. Acta 105 (1965) 313–324. [PMID: 5849820]
2.  Brühmüller, M., Möhler, H.K. and Decker, K. Covalently bound flavin in D-6-hydroxynicotine oxidase from Arthrobacter oxidans. Purification and properties of D-6-hydroxynicotine oxidase. Eur. J. Biochem. 29 (1972) 143–151. [PMID: 4628374]
3.  Brandsch, R., Hinkkanen, A.E., Mauch, L., Nagursky, H. and Decker, K. 6-Hydroxy-D-nicotine oxidase of Arthrobacter oxidans. Gene structure of the flavoenzyme and its relationship to 6-hydroxy-L-nicotine oxidase. Eur. J. Biochem. 167 (1987) 315–320. [PMID: 3622516]
4.  Schenk, S., Hoelz, A., Krauss, B. and Decker, K. Gene structures and properties of enzymes of the plasmid-encoded nicotine catabolism of Arthrobacter nicotinovorans. J. Mol. Biol. 284 (1998) 1323–1339. [PMID: 9878353]
5.  Koetter, J.W. and Schulz, G.E. Crystal structure of 6-hydroxy-D-nicotine oxidase from Arthrobacter nicotinovorans. J. Mol. Biol. 352 (2005) 418–428. [PMID: 16095622]
[EC 1.5.3.6 created 1972, modified 2015]
 
 
EC 1.5.99.4     
Accepted name: nicotine dehydrogenase
Reaction: (S)-nicotine + acceptor + H2O = (S)-6-hydroxynicotine + reduced acceptor
Other name(s): nicotine oxidase; D-nicotine oxidase; nicotine:(acceptor) 6-oxidoreductase (hydroxylating); L-nicotine oxidase
Systematic name: nicotine:acceptor 6-oxidoreductase (hydroxylating)
Comments: A metalloprotein (FMN). The enzyme can act on both the naturally found (S)-enantiomer and the synthetic (R)-enantiomer of nicotine, with retention of configuration in both cases [4].
References:
1.  Behrman, E.J. and Stanier, R.Y. The bacterial oxidation of nicotinic acid. J. Biol. Chem. 228 (1957) 923–945. [PMID: 13475371]
2.  Decker, K. and Bleeg, H. Induction and purification of stereospecific nicotine oxidizing enzymes from Arthrobacter oxidans. Biochim. Biophys. Acta 105 (1965) 313–324. [PMID: 5849820]
3.  Hochstein, L.I. and Dalton, B.P. The purification and properties of nicotine oxidase. Biochim. Biophys. Acta 139 (1967) 56–68. [PMID: 4962139]
4.  Hochstein, L.I. and Rittenberg, S.C. The bacterial oxidation of nicotine. II. The isolation of the first oxidative product and its identification as (1)-6-hydroxynicotine. J. Biol. Chem. 234 (1959) 156–160. [PMID: 13610912]
[EC 1.5.99.4 created 1972]