Prokaryotic Expression and Purification of Recombinant Human IFN-beta

Objective: To set up a optimal method of fermentation, refolding and purification of human interferon beta ( 17 Ser IFN β). Methods: The effect of different culture medium and induction time by thermal on the contents of 17 Ser IFN β were observed The optimal condition for purification of 17 Ser IFN β was also studied by changing pH, concentration of protein and chromatography procedure. Results: The expression level of 17 Ser IFN β increased significantly in M9 culture medium containing glycerol, casein hydrolysate and trace element. The optimal induction time for 17 Ser IFN β expression was 4hr and the expression quantity could reach 20% of total protein under the condition. The soluble IFN β in SDS could be extracted into organic phase by 2 eutanol and the purity could reach 80%. High molecule weight protein was excluded from 17 Ser IFN β after S200 gel permision chromatography and the purity could reach over 90%. The buffer was converted to that with pH8 by Superdex G25. After refolding, the product was refined by C4 reverse phase chromatography with a final purity over 98% and the biological activity more than 3×10 7 U/mg. Conclusion: The optimal condition of recombinant human 17 Ser IFN β was successfully established, which can be used for scale up production in the future.