GPX activity consists in the detoxification of hydrogen peroxide, and is one of the most important ubiquitous antioxidant enzymes involved in antioxidant homeostatic control. For the ubiquitous distribution, those proteins are well suited for molecular evolution studies also in consideration of the fact that, for they multifunctional role, may be important for the adaptation of organisms to peculiar environments.

The Antarctic species have an interesting evolutionary history because they have developed some adaptations that allow them to survive and to breed in waters where the temperature, oxygen and salt concentration deviate significantly from the average recorded in the temperate waters. They represent paradigmatic cases for adaptation to different temperatures and salinities in their environment.

Specimens of Gymnodraco acuticeps, a teleost fish widely distributed in Antarctic Ocean, were sampled in the Ross Sea (Terra Nova Bay, 74°42'S, 164°7'E) during the XVII Italian Antarctic Expedition. cDNA sequence of Se-GPXhas been obtained from hepatic tissue by a combination of RT-PCR, 3' and 5'RACE techniques. The obtained nucleotide sequence and the deduced amino acid sequence were compared to those of other teleosts.

The obtained nucleotide sequences have been compared with those of homologous genes already available in Genbank and have been used for phylogenetic analysis.

(Supported by P.N.R.A and M.I.U.R. grants)