Résumé
Nowadays,small peptides are always expressed in the form of fusion protein.The expression product contains many superfluous amino acids which can affect the biological functions of small peptides even expressed by GST fusion protein expression system.SUMO protease can cut SUMO fusion protein expressed by fusion expression system without any amino acid residues left on target protein thus become a hot topic in this field.Recombinant His-UlP1/pET3c/BL21(DE3)engineering strain was constructed by genetic engineering technology and the expression conditions were optimized in shake flaks.The process of high density fermentation was explored and different purification conditions were detected by chromatography.The results showed that SUMO protease could be expressed well after inducing the engineering strain by IPTG of 1.0mmol/L at 30℃ for 6 hours.The expression level of the strain in fermentation pots could reach 24.3% analyzed by SDS-PAGE.The purity of SUMO protease was more than 98% after further purification by cation exchange chromatography.The yield was 355mg SUMO protease per liter fermentation liquid.Western blot analysis demonstrated that there were immune reactions between IlP1 and 6?His antibodies,so it has established a good foundation for large-scale industralazation in the future.