CAT and inflammatory bowel disease: However, impaired endogenous enzymatic antioxidants, including superoxide dismutases (SOD), catalases (CAT), glutathione peroxidases (GSH-Px), and glutathione reductases (GRx), and the enhanced production of free radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), are commonly associated with the development of IBD [7].