Abstract: Objective To study the expression, purification and biological activity of the epitopc peptide of human tyrosinase antigen.Methods The target gene, encoding the 240-300 epitope regions of human tyrosinase, was cloned to the prokaryotic expression-veckor pGEX-4T-2, which was then transfected into E.coli BL21.The protein expression was induced by IPTG(isopropyl-(3-D-thiogalactoside)and examined with SDS-PAGE and Western blotting.The biological activity of the target protein was detected with ELISA.Results The recombinant expression vector was constructed successfully.SDS-PAGE and Western blotting verified the successful expression ofrecombinant protein Quantification by gel analysis system revealed that the recombinant protein amounted to 90% of the total protein content of the bacterial cells.With the application of glutathione S-transferase(GST)purification kit, the purity of the recombinant protein reached over 95%.The purified protein was confirmed by ELISA analysis to he able to bind to IgG from vitiligo patients.Conclusion Our results suggest that the epitope peptide of human tyrosinase antigen is expressed successfully, with biological activity confiimed.

Key words: Vitiligo, Monophenol monooxygenase, Prokaryotic expression