Abstract: Abstract:【Objective】To investigate the expression characteristic of duck leptin in E.coli BL21 and the bioactivity of the expression product.【Method】Constructive the recombinant duck leptin gene prokaryotic expression strain. The recombinant strain was induced in different time and different concentrations of IPTG. After purification, renaturation and condensation, the product was injected into Kunming mice. The body weight, food intake and body weight of mice were analyzed.【Result】The fusion protein was specifically expressed. The results of SDS-PAGE analysis indicated that the molecular weight of the fusion protein was about 20kDa, which included the 16kDa protein expressed from duck leptin gene. The aimed protein was expressed with the induction of 0.2mmol/L IPTG, which was about 57% of total protein in bacteria. The recombinant protein reduced body weight、food intake and body weight on the testing in Kunming mice.【Conclusion】Duck leptin was high effective in E.coli BL21. The purified recombinant protein was proved to be biologically activity.

Key words: Duck, leptin gene, expression, bioactivity