Purification of human interleukin-4 from secreted Escherichia coli mutants

摘要

Active recombinant human IL-4 is purified from a crude fermentation broth of a secreted E. coli mutant by subjecting said solution to selective chromatogrphy on a zinc-chelating agarose column at pH 7.2 in a buffer containing a high concentration of sodium chloride, i.e., about 1M sodium chloride, washing first with a phosphate buffer at pH 7.2 containing 1.0M sodium chloride then with a buffer containing 10% glycerol and eluting at pH 5.0. The resulting purified active recombinant human IL-4 solution is further treated by cation exchange chromatography, concentration by diafiltration up to 20 mg/mL and size exclusion gel chromatography using a citrate buffer at pH 4.5.