Reaction: nicotinate + H2O + NADP+ = 6-hydroxynicotinate + NADPH + H+
For diagram click here.
Other name(s): nicotinic acid hydroxylase; nicotinate hydroxylase
Systematic name: nicotinate:NADP+ 6-oxidoreductase (hydroxylating)
Comments: A flavoprotein containing non-heme iron. The enzyme is capable of acting on a variety of nicotinate analogues to varying degrees, including pyrazine-2-carboxylate, pyrazine 2,3-dicarboxylate, trigonelline and 6-methylnicotinate. The enzyme from Clostridium barkeri also possesses a catalytically essential, labile selenium that can be removed by reaction with cyanide.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9059-03-4
References:
1. Holcenberg, J.S. and Stadtman, E.R. Nicotinic acid metabolism. 3. Purification and properties of a nicotinic acid hydroxylase. J. Biol. Chem. 244 (1969) 1194-1203. [PMID: 4388026]
2. Gladyshev, V.N., Khangulov, S.V. and Stadtman, T.C. Properties of the selenium- and molybdenum-containing nicotinic acid hydroxylase from Clostridium barkeri. Biochemistry 35 (1996) 212-223. [PMID: 8555176]
3. Gladyshev, V.N., Khangulov, S.V. and Stadtman, T.C. Nicotinic-acid hydroxylase from Clostridium barkeri - electron-paramagnetic-resonance studies show that selenium is coordinated with molybdenum in the catalytically active selenium-dependent enzyme. Proc. Natl. Acad. Sci. USA 91 (1994) 232-236. [PMID: 8278371]
4. Dilworth, G.L. Occurrence of molybdenum in the nicotinic-acid hydroxylase from Clostridium barkeri. Arch. Biochem. Biophys. 221 (1983) 565-569. [PMID: 6838209]
5. Dilworth, G.L. Properties of the selenium-containing moiety of nicotinic-acid hydroxylase from Clostridium barkeri. Arch. Biochem. Biophys. 219 (1983) 30-38.
6. Nagel, M. and Andreesen, J.R. Purification and characterization of the molybdoenzymes nicotinate dehydrogenase and 6-hydroxynicotinate dehydrogenase from Bacillus niacini. Arch. Microbiol. 154 (1990) 605-613.