Fusion Expression of Cecropin B in Escherichia coli with Lactose as the Inducer

According to the amino acid sequence of Cecropin B and the bias coden for genes of Escherichia coli,the Cecropin B gene was artificial synthesized and subcloned into an E.coli expression vector pET-41a.The recombined plasmid pET41a-cecB was then transformed into E.coli BL21(DE3).Lactose was used as an inducer instead of IPTG.Detected by SDS-Page,the result demonstrated that the proper optimization of induction conditions is to add 0.25 mmol/L(termical concentration) lactose at OD 1.0 and induce 5 h.The pET41a-cecB expression level 17.1% of total cellular protein was achieved.The result indicated that lactose could be used as a promising inducer in the production of recombined Cecropin B.