Expression of Tα1-TP5 fusion peptide in E.coli induced by lactose

Purpose To study the use of lactose instead of IPTG as the inducer for the expression of recombinant thymosin 1-thymopentin fusion peptide(Tα1-TP5),and to optimize the expression conditions.Methods Under the shake flask fermentation conditions,the influence of culture medium,inducer concentration,induction starting time,induction time,induction temperature and induction method on the expression level of target protein was analyzed by SDS-PAGE electrophoresis and AlphaEase gel electrophoresis image analysis system,and results were compared with those induced by IPTG.Results When using TB as the medium,adding final induction concentration of 1 g/L of lactose to the middle and late logarithmic phase of bacteria to induce for 6 h at 37 ℃,the GST-Tα1-TP5 fusion protein accounted for 35% of the bacterial total protein,mainly in a soluble form,and the expression level was the same as that induced by IPTG.The result of adding lactose once had no significant diffience compared with that of adding four times.Conclusion Lactose can be used as the inducer instead of IPTG for the expression of Tα1-TP5.