Abstract: After cloning into the expression vector pET28a, the lactoferricin B gene was transformed into BL-21 E.coli prokaryotic expression system. By selecting expression temperature and IPTG concentration, lactoferricin B gene was expressed at high level in prokaryotic cells. The expression of lactoferricin B was detected by tricine-SDS-PAGE protein electrophoresis and functional test, and it was proved to be the lactoferricin B. The result also showed that the gene of lactoferricin B can be highly expressed in prokaryotic expression system, and the expression product accounts for about 21% of total bacterial proteins with biology activity.

Key words: lactoferricin B gene, prokaryotic expression system, Tricine-SDS-PAGE, functional test