Abstract: A method for purifying and recovering biologically active somatotropin monomers from refold solution following the solubilization and naturation of refractile bodies of host cells produced by recombinant DNA methodology. The purification process is based on the discovery that somatotropin monomers and somatotropin oligomers having overlapping isoelectric points may nevertheless be separated by selective precipitation over a narrow pH range. Host cell residues including proteins, pyrogens and other impurities present in the refold solution are effectively removed in the process. The purified somatotropin monomers recovered from solution after removing precipitated solids are suitable for parenteral application to target animals without further purification.

Abstract: A method for purifying and recovering biologically active somatotropin monomers from refold solution following the solubilization and naturation of refractile bodies of host cells produced by recombinant DNA methodology. The purification process is based on the discovery that somatotropin monomers and somatotropin oligomers having overlapping isoelectric points may nevertheless be separated by selective precipitation over a narrow pH range. Host cell residues including proteins, pyrogens and other impurities present in the refold solution are effectively removed in the process. The purified somatotropin monomers recovered from solution after removing precipitated solids are suitable for parenteral application to target animals without further purification.

Abstract: A method for solubilization and naturation of somatotropin protein from refractile bodies of host cells is disclosed. The method embraces the discovery that an aqueous solution of urea, or dimethylsulfone, or mixtures of urea and dimethylsulfone, can be effectively used to solubilize refractile bodies containing such somatotropin protein. Once solubilized, somatotropin protein can be natured in an aqueous solution of urea, or dimethylsulfone, or mixtures of urea and dimethylsulfone, by contacting the solution with a mild oxidizing agent for a time sufficient to result in the formation of the disulfide bonds. Naturation can efficiently occur even at high protein concentration, in an impure preparation and in the absence of reducing agent.

Abstract: A method for solubilization and naturation of somatotropin protein from refractile bodies of host cells is disclosed. The method embraces the discovery that an aqueous solution of urea, or dimethylsulfone, or mixtures of urea and dimethylsulfone, can be effectively used to solubilize refractile bodies containing such somatotropin protein. Once solubilized, somatotropin protein can be natured in an aqueous solution of urea, or dimethylsulfone, or mixtures of urea and dimethylsulfone, by contacting the solution with a mild oxidizing agent for a time sufficient to result in the formation of the disulfide bonds. Naturation can efficiently occur even at high protein concentration, in an impure preparation and in the absence of reducing agent.

Abstract: Methods of solubilization and naturation of somatotropin protein from refractile bodies of host cells are disclosed. The solubilization methods embrace the discovery that an aqueous urea solution can be effectively used to solubilize refractile bodies containing such somatotropin protein. Surprisingly, it has been further found that once solubilized, such somatotropin protein can be natured in the urea solution by contacting the solution with a mild oxidizing agent for a time sufficient to result in the formation of the disulfide protein. Naturation can efficiently occur even at high protein concentration, in an impure preparation and in the absence of reducing agent.