Preparation and characterization of mono PEGylated recombinant human interferon omega

The amino group PEGylation of rhIFNω with monomethoxy polyethylene glycol succinimidyl succinate (mPEG-SS, 20 000) was investigated, and the modified mixture was separated and purified by ion exchange chromatography and gel filtration chromatography.  Under the optimized purification conditions, the average content of mono PEG-rhIFNω in the collect liquid reached 182 μg·mL⁻¹.  The average purified yield of mono PEG-rhIFNω exceed to 22%, and the purity of mono PEG-rhIFNω was greater than 98% by SDS-PAGE and RP-HPLC.  Relative molecular mass of mono PEG-rhIFNω was 43 790 detected by MALDI-TOF MS.  The apparent molecular mass measured by SDS-PAGE was about 60 810.  The purified PEG-rhIFNω has the characteristics of typical PEGylated protein.  Activity reservation rate of mono PEG-rhIFNω was 15.0%, while the antigenicity decreased by at least 64 folds.  In addition, the acid stability, thermal stability and stability in serum and trypsin solution of mono PEG-rhIFNω were markedly better than those of the rhIFNω.  The pharmacological properties of mono PEG-rhIFNω were significantly improved.  The prepared PEG-rhIFNω might be developed to a novel safe and long-acting interferon.