CAT and male infertility: Antioxidant enzymes and molecules such as superoxide dismutases, glutathione (GSH), and catalases are largely abundant in semen plasma and sperm cells.17 Most of these genes, including nuclear factor erythroid 2-related factor 2, superoxide dismutases, catalases, glutathione-s-transferase, glutathione peroxidase and nitric oxide synthase harbor sequence variants in humans, which in turn may cause male infertility in different ways.