<prompt> Selenium is a co-factor forGlutathione peroxidaseGlutathione reductaseGlutathione synthetaseGlutathione dehydrogenase  <response>: Selenium is component of selenocysteine, glutathione peroxidase, thioredoxin, deiodinaseThe peroxides that are formed by radical damage to lipids in membranes and plasma lipoproteins are reduced to hydroxy fatty acids by glutathione peroxidase.Ref: Harper;s Biochemistry; 30th edition; Pg: 567 