Nicotine dehydrogenase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are nicotine, water and an electron acceptor. Its products are 6-hydroxynicotine and the corresponding reduced acceptor.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with other acceptors. The systematic name of this enzyme class is nicotine:acceptor 6-oxidoreductase (hydroxylating). Other names in common use include nicotine oxidase, D-nicotine oxidase, nicotine:(acceptor) 6-oxidoreductase (hydroxylating), and L-nicotine oxidase. It is a metalloprotein that contains flavin mononucleotide.