SOD2 and obesity due to melanocortin 4 receptor deficiency: Therefore, NAFL, but not obesity per se, was accompanied by the increased expression of NFE2L2 targets genes, including NOX4, which encodes a ROS-producing enzyme, and NQO1, SOD2, and CAT, which encode key antioxidant defense enzymes, but these declined with more advanced disease and fibrosis.