Peroxiredoxin 6 from the clawed frog Xenopus laevis: cDNA cloning, enzyme characterization, and gene expression...

The Xenopus laevis 1-Cys-peroxiredoxin (peroxiredoxin 6, Prx6) gene was cloned and expressed in Escherichia coli. The enzymatic properties of the recombinant protein were characterized and compared to those of human Prx6. Xenopus laevis Prx6 has 224 amino acid residues including five Cys, one of which, Cys47, is located in the active center determining peroxidase activity. The stability and activity of X. laevis Prx6 relative to hydrogen peroxide and tret-butyl hydroperoxide are very similar to corresponding values for human Prx6. Both enzymes have temperature optimum at 37 degrees C, but the clawed frog enzyme retains no less than 50% of activity over a wider temperature interval (10-50 degrees C) than the human one (25-50 degrees C). The expression of X. laevis prx6 at different stages of development was investigated. The level of gene expression increased during development, especially at stages 33-43 during formation of the lungs, when heartbeat and hatching begins.