MetaCyc Enzyme: nicotinate dehydrogenase (cytochrome)

Synonyms: nicotinate hydroxylase

Species: Pseudomonas fluorescens TN5

It has been shown that the oxygen of the hydroxyl group is derived from water, rather than molecular oxygen. The identity of the physiological electron acceptor in P. fluorescens is not known, but there is evidence that nicotinate dehydrogenase is linked to the cytochrome respiratory chain [Hunt58].

The molecular mass of 80 kDa was determined by SDS-PAGE. Gel-permeation HPLC gave a molecular mass of 100 kD [Hurh94].

Locations: membrane

Molecular Weight of Polypeptide: 80 kD (experimental) [Hurh94]

Gene-Reaction Schematic

Gene-Reaction Schematic

GO Terms:
Cellular Component:
GO:0016020 - membrane [Hurh94]

Enzymatic reaction of: nicotinate dehydrogenase

Inferred from experiment

EC Number:

nicotinate + 2 an oxidized cytochrome + H2O → 6-hydroxynicotinate + 2 a reduced cytochrome + 2 H+

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

Alternative Substrates for nicotinate: 3-pyridinesulfonate [Hurh94]

In Pathways: nicotinate degradation I

Inhibitors (Unknown Mechanism): Hg2+ [Hurh94], Cu2+ [Hurh94], Ag+ [Hurh94], p-chloromercuribenzoate [Hurh94], N-ethylmaleimide [Hurh94]Kinetic Parameters:
Substrate Km (μM) Citations
nicotinate 110.0 [Hurh94]

T(opt): 50 °C [Hurh94]

pH(opt): 8.3 [Hurh94]


Hunt58: Hunt, A.L., Hughes, D.E., Lowenstein, J.M. (1958). "The hydroxylation of nicotinic acid by Pseudomonas fluorescens." Biochem J 69(2);170-3. PMID: 13546162

Hurh94: Hurh B, Yamane T, Nagasawa T (1994). "Purification and characterization of nicotinic acid dehydrogenase from Pseudomonas fluorescens TN5." J. Ferment. Bioeng. 78, No. 1, 19-26.

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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
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