Catalyzes the reduction of the double bond of an array of alpha,beta-unsaturated aldehydes and ketones. It also reduces the nitro group of nitroester and nitroaromatic compounds. It could have a role in detoxification processes. A + H(+) + NADPH = AH2 + NADP(+) Inhibited by p-hydroxybenzaldehyde (pHBA) and p-nitrophenol (pNP). The highest catalytic efficiency was observed with N-ethylmaleimide for which the KM is inferior to 1.0 uM. Homotetramer. Composed of a dimer of active dimers. By toxic xenobiotic compounds (2,4,6-trinitrotoluene and nitroglycerin), and in response to oxidative stress (hydrogen peroxide and paraquat). Forms a charge transfer complex with a variety of phenolic compounds. Belongs to the NADH:flavin oxidoreductase/NADH oxidase family. NamA subfamily.