NQO2

NQO2 (quinone reductase 2, QR2) is a flavin adenine dinucleotide (FAD)-dependent oxidoreductase that catalyzes two-electron reduction of quinones and related electron acceptors, thereby participating in cellular redox regulation and quinone metabolism^[1][2]. Mechanistically, NQO2 belongs to the quinone oxidoreductase family but differs from many classical reductases because it uses reduced nicotinamide derivatives such as N-ribosyldihydronicotinamide (NRH) rather than NADH or NADPH as efficient electron donors^[1][3][4]. This distinctive cofactor specificity has driven interest in NQO2 as a regulator of redox biology, reactive oxygen species generation, and cellular metabolic responses^[3][4]. In disease-relevant settings, altered NQO2 expression and activity have been associated with oxidative stress-related processes, neurodegeneration, learning and memory regulation, and Alzheimer’s disease-related phenotypes^[5][6]. Experimental studies further indicate that genetic or pharmacological suppression of NQO2 can reduce metabolic burden and oxidative stress while improving disease-associated phenotypes in preclinical models^[6]. Compared with the closely related isoform NQO1, NQO2 shares structural homology and overlapping substrate classes but exhibits fundamentally different cofactor utilization, making it an atypical oxidoreductase with distinct biological functions and regulatory properties^[1][3][4]. For experimental applications, NQO2 has attracted considerable attention as a druggable target, and selective inhibitors including S29434, resveratrol-derived compounds, and other mechanism-based ligands have been developed to probe NQO2-dependent pathways and evaluate therapeutic relevance in redox-associated disorders^[7][8].