关键词: alpha-interferon 2b;soluble expression;inclusion body;refolding;purification

Abstract: Alpha-interferon 2b (IFN 2b) was produced both in soluble and insoluble forms from
recombinant E. coli. The dissolution of the expressed IFN 2b in inclusion body was carried
out and it was found that the optimal condition to dissolve the expressed protein was 7
mol. L-1guanidininm salt solution at pH 3.0. The resultant solution was diluted 20 times
using pH 6.0 buffer to ref+ld the protein correctly. The cation exchange column was
employed to purify both refolded and soluble IFN 2b. For soluble IFN sample, high IFN 2b
recovery yield (92.1%) with 91.7% purity was obtained in the eluate. However, for refolded
IFN sample, only 72.7% ofIFN 2b was recovered with relatively low purity (56.8%) by cation
exchange chromatography. Although the expression level of insoluble IFN was higher than
that of co-expressed soluble IFN in this recombinant E.coli cells, the productivity of
bioactive IFN 2b was higher with soluble expressed IFN after primary purification process.
Soluble expression of foreign proteins in recombinant bacteria might be an alternative
strategy for efficient production of heterogeneous proteins due to high bioactivity and
simple downstream protein purification process.

Key words: alpha-interferon 2b, soluble expression, inclusion body, refolding, purification