Nicotinate dehydrogenase (cytochrome) (, nicotinic acid hydroxylase, nicotinate hydroxylase) is an enzyme with systematic name nicotinate:cytochrome 6-oxidoreductase (hydroxylating). This enzyme catalyses the following chemical reaction
<div align=center><small>nicotinate + a ferricytochrome + H<sub>2</sub>O 6-hydroxynicotinate + a ferrocytochrome + 2 H<sup>+</sup></small></div>
This two-component enzyme from Pseudomonas belongs to the family of xanthine dehydrogenases.