PURPOSE: To obtain a purified protein, produced according to a genetic engineering technique, separated and removed from a protein to which methionine residue is added, without containing the terminal methionine residue and useful as medicines, etc., such as interleukin-2 or interferon-α.
CONSTITUTION: This purified protein is obtained by transducing a recombinant gene in which a DNA capable of coding a protein such as interleukin-2 is integrated into a host such as Escherichia coil, transforming the Escherichia colt, inoculating the resultant transformant into a liquid culture medium, culturing the transformant at 37°C overnight by shaking, then transferring the culture solution to a jar fermenter, culturing the culture solution at 37°C for 8hr, centrifuging the resultant culture solution, collecting microbial cells, suspending the collected microbial cells in a 7M guanidine hydrochloride-0.1M tris hydrochloric acid buffer solution, stirring the suspension at 4°C for 1hr, carrying out the bacteriolysis, centrifuging the prepared lysate, providing a supernatant, then passing the obtained supernatant through an anion exchange column, adsorbing a protein, subsequently eluting the adsorbed protein with an NaCl concentration gradient, treating the eluate by gel filtration and high-performance liquid chromatography and purifying the protein. Thereby, the objective purified protein without containing a protein in which methionine residue is added is obtained.
YAMADA TAKAHISA
KAWAHARA KENJI
