NQO2 (N-ribosyldihydronicotinamide:quinone dehydrogenase 2) is a FAD-linked flavoprotein that catalyzes two-electron reductions of quinones and other electrophiles 1. Unlike its related enzyme NQO1, NQO2 uses dihydronicotinamide riboside (NRH) rather than NAD(P)H as an electron donor and is resistant to typical NQO1 inhibitors such as dicoumarol 1. The enzyme contributes to cellular detoxification pathways by metabolizing biogenic and xenobiotic quinones, including antitumor drugs, with both toxifying and detoxifying functions 2. NQO2 exhibits unique structural features including a specific metal binding site not present in NQO1 1. Beyond quinone metabolism, NQO2 may regulate oxidative stress, inflammation, and autophagy 2. The enzyme shows wide tissue distribution with highest expression in liver and testis 3. NQO2 is highly polymorphic, with variants affecting disease susceptibility - hypomorphic alleles linked to cancer risk while hypermorphic variants associate with neurodegenerative diseases 2. Polymorphisms in NQO2 have been associated with esophageal cancer susceptibility in some populations 4. Hepatic NQO2 activity reaches adult levels by birth but clearance capacity matures gradually until teenage years 5.