Glutathione reductase contains the following metal:

In red blood cells the pentose phosphate pathway provides NADPH for the reduction of oxidized glutathione catalyzed by glutathione reductase, a flavoprotein containing FAD. Reduced glutathione removes H2O2 in a reaction catalyzed by glutathione peroxidase, an enzyme that contains the selenium analogue of cysteine (selenocysteine) at the active site (Figure 21-3). The reaction is impoant, since accumulation of H2O2 may decrease the life span of the erythrocyte by causing oxidative damage to the cell membrane, leading to hemolysis Ref: Harper 28th edition, chapter 21.