Expression, Purification and Activity Analysis of Consensus Interferon Mutant Produced in Pichia pastoris

An artificial gene for consensus interferon mutant was synthesized by using favored codons of the yeast Pichia pastoris . The gene was cloned into the secretory expression vector pMEX9K, and the recombinant vector pMEX CIFNm was linearized and transformed into GS115 for expression. The culture supernatant of transformants had the antiviral activity after inducement with methanol. The purity of recombinant protein reached over 95% through the steps of ion exchange, hydrophobic interaction, size exclusion chromatography. The first 5 amino acid sequence of the N terminal was consistent with the theoretical sequence. Its molecular weight measured by MS agree with the theoretical value 19 3 kD. The specific activity of protein was similar to consensus interferon(infergen)——6×10 8 antiviral units/mg when assayed by the antiviral activity of WISH cells challenged with VSV virus and Lowry protein assay.