Activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione Reductase in Different Stages of Colorectal Carcinoma Digestive Diseases and Sciences Springer Nature Link An Investigation of the Succination of the Selenoproteins Thioredoxin Reductase and Glutathione Peroxidase Semantic Scholar A trifunctional enzyme with glutathione S transferase, glutathione peroxidase and superoxide dismutase activity ScienceDirect 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 Enzymatic and Non enzymatic defense against ROS