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).
