Background：NQO2 （EC 1.10.99.2） is a flavoprotein that catalyzes the 2-electron reduction of various quinones, redox dyes, and the vitamin K menadione. NQO2 predominantly uses dihydronicotinamide riboside （NRH） as the electron donor. 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.
