NQO1 (NAD(P) H Dehydrogenase, Quinone 1) belongs to the NAD(P)H dehydrogenase (quinone) family and serves as a quinone reductase and it has NAD(P)H dehydrogenase (quinone) activity and cytochrome-b5 reductase activity. NQO1 catalyzes the 2-electron reduction of various quinones and redox dyes, such as, phyloquinone and the vitamin K, menadione. NQO1 proetin consists of 274 amino acids having molecular mass of 30 kDa. It exists in 3 isoforms produced by alternate splicing. NQO1 is associated with benzene toxicity, leukemia and post-chemotherapy diseases. It is expressed in adipose tissue, blood, brain, bone, spleen, etc.