CAT and Infertility: Alterations in the expression of antioxidant enzymes, such as superoxide dismutase (SOD), which catalyzes the cleavage of superoxide anion radicals into hydrogen peroxide, catalase (CAT), and glutathione peroxidase (GPx), which decreases the hydrogen peroxide content in cells through the formation of water and oxygen [44] (Figure 2), have been reported in infertile patients [45] and correlate with a reduced fertilizing capacity [46] due to DNA fragmentation and sperm abnormalities [47].