[Selenic enzymes as factors protecting against oxygen stress]

Oxygen stress is an increase of activity of free oxygen radicals in a degree exceeding the possibility of their control by the antioxidative system of the organism. Since glutathione peroxidase was indicated as a selenium-dependent enzyme of the antioxidative system, many later studies did not confirm that function, indicating rather the participation of that protein in selenium transport. Lately, two other selenoproteins were discovered, one being a hepatic selenoprotein, participating in repairing of the damage caused by free radicals, the other being a blood serum selenoprotein which is supposed to act as a carrier. The participation of these selenoproteins in the antioxidative system of the organism is not well known.