Selenium: Biochemical Role as a Component of Glutathione Peroxidase

When hemolyzates from erythrocytes of selenium-deficient rats were incubated in vitro in the presence of ascorbate or H 2 O 2 , added glutathione failed to protect the hemoglobin from oxidative damage. This occurred because the erythrocytes were practically devoid of glutathione-peroxidase activity. Extensively purified preparations of glutathione peroxidase contained a large part of the 75 Se of erythrocytes labeled in vivo. Many of the nutritional effects of selenium can be explained by its role in glutathione peroxidase.