Molecular characterization and functional analysis of peroxiredoxin3 cDNA from black tiger shrimp (Penaeus monodon)

Peroxidase 3 (Prx‐3) is an important antioxidant protein that protects the body from the toxic effects of reactive oxygen species. In this study, the full‐length Prx3 cDNA sequence (PmPrx3) was isolated from Penaeus monodon. The PmPrx3 cDNA was 942 base pairs long and encoded a 227 amino acid polypeptide. The PmPrx3 protein showed high similarity (74%–83%) with the Prx3 protein from other species and contained the conserved Prx domain and peroxidase catalytic center. The results of reverse transcription polymerase chain reaction showed that PmPrx3 mRNA was universally expressed in all tested tissues. The level of PmPrx3 mRNA expression in the gills and hepatopancreas significantly changed after heavy metal exposure. Recombinant PmPrx3 protein (rPmPrx3) was obtained using a prokaryotic expression system and purified using affinity chromatography. Antioxidant activity assays showed that rPmPrx3 reduced insulin in the presence of dithiothreitol, suggesting that the anti‐oxidant function of rPmPrx3 was thiol‐dependent. In addition, Escherichia coli transferred with pET‐28a‐PmPrx3 was significantly protected in response to metal toxicity and H2O2 oxidative stress. In summary, our findings provided important insights into the mechanism of action of the Prx3 gene in environmental stress in P. monodon.