Abstract: 【Aim】 To establish a simple, quick and effective method to get a large number of bombyxin-Ⅱ (BBXⅡ). 【Methods】 Full-length cDNA of the bombyxin-Ⅱ gene from the silkworm (Bombyx mori) was obtained through RT-PCR technique, and its promoter sequences were cloned based on genome sequences of the silkworm. Meanwhile we got purified BBXⅡ protein by affinity chromatography. 【Results】 We obtained the cDNA of bombyxin-Ⅱ by reverse transcription of the mRNA from the head of the silkworm and built the prokaryotic expression vector pET28a-BBXⅡ. The BBXⅡwas highly expressed by IPTG induction. Then we successfully got a large amount of purified BBXⅡ by HisTrap HP affinity chromatography. 【Conclusion】 The prokaryotic expression and protein purification technology that we built is a simple and effective method to obtain a lot of preparation of BBXⅡ. The results lay a foundation for further research of the secretion and action mechanisms of BBX and for discovery of BBX hypoglycemic drugs by using prokaryotic expression system.

Key words: Bombyx mori, insulin like peptide, bombyxin (BBX), gene cloning, prokaryotic expression, protein purification