Study on Purification and Renaturation of His6-?TNF?Fusion Protein (IB) / 中国肿瘤生物治疗杂志

ABSTRACT

The E. coli BL21(DE3) strain bearing the plasmid(T_7lac/His6-tag) with the h?TNF?recombinant gene was grown in LB medium containing SO?g/ml kanamycin, at 37 ℃ , up to the late logarithmic phase(OD590 ~ 0.5)then induced with IPTG (final concentration lmmol/L)for 5 hours. SDS-PAGE analysis revealed that expression level of the product(His6-?TNF?was up to 45% of the total bacterial proteins and was mainly as insoluble inclusion bodies ( IBs) . After cell lysis, the IBs was separated by centrifugation, dissolved in 7mol/L urea, then purified by Ni column ( Ni~(2+) -Sepharose 6B) . And the purity of more than 95% and the recovery of about 90% were obtained. The purified product was refolded with the renaturation buffer under low temperafure(