NQO2 is a flavoprotein that catalyzes the 2-electron reduction of diverse quinones, redox dyes, and the vitamin K menadione. NQO2 mainly uses dihydronicotinamide riboside(NRH) as the electron donor. NQO2 catalyzes the metabolic detoxification of quinones and their derivatives to hydroquinones. This detoxification process protects cells against quinone-induced oxidative stress, cytotoxicity and mutagenicity.