NADH Dehydrogenase, Quinone 2 (NQO2)

NQO2 is a phase II detoxification enzyme which can carry out two or four electron reductions. Its mechanism of reduction is via a covalently bound zinc ion and a cocrystalized FAD. NQO2 contains two chains homologous in AA sequence but 7% different in structure. As a result, NQO2 contains two similar yet unique active sites. An important function of NQO2 is its activation on NRH. NQO2 can be inhibited by resveratrol.NQO2 could bind estrone-3,4-quinone (E1-3,4-Q) and estradiol-3,4-quinone (E2-3,4-Q). Preliminary kinetic studies revealed that NQO2 was faster in reducing and deactivating the estrogen quinones than NQO1. The reduction of E1-3,4-Q and E2-3,4-Q by NQO2 was confirmed by ultraviolet and liquid chromatography-tandem mass spectrometry assays.