The enzyme apparently serves as a quinone reductase in connection with conjugation reactions of hydroquinones involved in detoxification pathways as well as in biosynthetic processes such as the vitamin K-dependent gamma-carboxylation of glutamate residues in prothrombin synthesis. 1-(beta-D-ribofuranosyl)-1,4-dihydronicotinamide + a quinone + H(+) = a quinol + beta-nicotinamide D-riboside Binds 1 zinc ion per subunit. Inhibited by melatonin, resveratrol and 5-hydroxytryptamine. Homodimer. Uses dihydronicotinamide riboside (NRH) rather than NAD(P)H as an electron donor. Belongs to the NAD(P)H dehydrogenase (quinone) family.