High level expression of the LTB subunit of Escherichia coli heat-labile enterotoxin in prokaryocyte

The E.coli heat-labile enterotoxin B subunit gene was amplified from the plasmid EWD299 by the method of PCR,and cloned into the expressing vector pET28a.The recombinant plasmid was then transformed into the compound cell BL21(DE3)plyss. Induced with IPTG,these cells expressed the recombinant protein LTB,identified by SDS-PAGE and Western blot.The amount of the expressed recombinant protein was about 38 % of the total cells scaled by gel thin scanner instrument CS-9000.