NQO1 is a member of the NAD(P)H dehydrogenase (quinone) family and encodes a cytoplasmic 2- electron reductase. This protein apparently serves as a quinone reductase in connection with conjugation reactions of hydroquinons involved in detoxification pathways as well as in biosynthetic processes such as the vitamin Kdependent gamma-carboxylation of glutamate residues in prothrombin synthesis.