REDUCTION OF THYMINE HYDROPEROXIDE BY PHOSPHOLIPID HYDROPEROXIDE GLUTATHIONE-PEROXIDASE AND GLUTATHIONE TRANSFERASES

Thymine hydroperoxide (5-hydroperoxymethyluracil), a model compound re presenting products of oxidative damage to DNA, is a substrate for glu tathione peroxidase and some isoforms of glutathione transferase. In t his paper, we show that selenium-dependent human phospholipid hydroper oxide glutathione peroxidase (Se-PHGPx) exhibits about four orders of magnitude higher activity on thymine hydroperoxide than that of other human enzymes such as selenium-dependent glutathione peroxidase and va rious representatives of glutathione transferases. The results indicat e that Se-PHGPx may be an important enzyme in repairing oxidatively da maged DNA. (C) 1997 Federation of European Biochemical Societies.