Enzymatic and Non enzymatic defense against ROS Figure 1 from Glutathione S transferase, catalase, superoxide dismutase, glutathione peroxidase, and lipid peroxidation as a biomarkers of oxidative stress in snails: A review Semantic Scholar Activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione Reductase in Different Stages of Colorectal Carcinoma Digestive Diseases and Sciences Springer Nature Link Glutathione Peroxidase Protects against Peroxynitrite mediated Oxidations Journal of Biological Chemistry GLUTATHIONE PEROXIDASE, SELENIUM AND VITAMIN E Free radicals "steal" electrons from the chemical structures that make up cell membranes. When the structures making up the cell membranes loose electrons they too become