| Abstract: | Two different genes of peroxiredoxin 6 are encoded in the genome of Xenopus laevis: xen1 (Acc.no. EMBL Data Bank - BCO54278) and xen2 (Acc.no. EMBL Data Bank - BC540309). Both genes were cloned and expressed in Escherichi coil. Proteins were purified and analyzed. The amino acid sequences of the enzymes Xen1 and Xen2 are 95% identical with the same peroxidase activity, pH and temperature optimums, as well as thermostability, being approximately equal. The expression of peroxiredoxin 6 genes significantly differ during ontogenesis of X. laevis. The expression of xen1 starts on a later stage of development 47-48, while the gene xen2 is expressed on all stages of development with the same increase starting from stage 0-5. The level of xen2 expression in embryos increased after incubation in presence of hydrogen peroxide. The comparison of amino acid sequences of proteins Xen1 and Xen2 shows that only the enzyme Xen2 may have phospholipase activity, since it has residues of phospholipase A2 active center: Ser31, His25, Asp139. |
