hsTRAIL gene(amino acids 114-281) was amplified by means of PCR using human liver cDNA as a template and cloned into three different expressing vectors including pET30a, pET25b and pJLA503. SDS-PAGE analysis indicated that pET30a system was the best among the three expression systems after induction by IPTG and the expressed TRAIL protein accounts for about 40% of the total bacterial protein. Renaturation of TRAIL by two methods was studied. Data showed that the renaturation rate by dilution was higher than that by dialysis. Purified protein showed obviously biological activity which was similar to that of standard.
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