NQO2 is a 231 amino acid protein (25956 MW) that is 43 amino acids shorter than NQO1 at its carboxy-terminus. The human NQO2 cDNA and protein are 54 and 49% similar to the human liver cytosolic NQO1 cDNA and protein. NRH: quinone oxidoreductase 2 (NQO2) is a cytosolic and ubiquitously expressed flavoprotein that catalyzes the two-electron reduction of quinone to hydroquinones. NQO2 catalyzes the metabolic reduction of quinones and provides protection against myelogenous hyperplasia and chemical carcinogenesis. Disruption of the NQO2 gene in mice leads to γ radiation-induced myeloproliferative diseases. NQO2 is involved in ROS generation and subsequent cytotoxicity in oocytes and its inhibition can restore oocyte maturation and embryo development, suggesting NQO2 as a pharmacological target for infertility cure.