Purification and Stability Expression of Open Reading Frames encoding Fusion and Non Fusion Human Interferon Alpha-2a produced in Methilotropic Yeast Pichia pastoris

Recombinant human interferon alpha-2a (hIFNα-2a) is therapeutic protein that widely used in hepatitis B/C and several cancer treatments. We developed higher molecular weight of hIFNα-2a to improve protein pharmacokinetic profile. The protein was designed as a fusion protein with human serum albumin as protein tag. The protein was produced in Pichia pastoris with 85 kDa in size. This research was aimed to purify, characterize and determine the stability expression of open reading frame (ORF) encoding Fusion and Non fusion forms of hIFNα-2a. The proteins were purified using affinity chromatography and characterized using SDS PAGE and Western Blotting methods. Protein recovery yield was determined by ELISA. Stability expression was applied in generation time until 90th generation. The results showed that the Fusion and Non fusion proteins were successfully purified with 74-79% of protein recovery. The proteins can be recognized by specific monoclonal antibody and verified as hIFNα-2a Fusion and Non fusion with 85 kDa and 19 kDa in size respectively. The expression stability showed that the proteins were still produced in Pichia pastoris until 90th generation time with no significant difference of expression level. To conclude, the expression level of ORFs encoding Fusion and Non fusion hIFNα-2a was stable until 90th generations.