Protein Refolding Method

A method for producing a protein having a restored native higher-order structure, the method comprising:

• (1) bringing a protein which has become insoluble or lost its native higher-order structure into contact at pH 6.5 to 9.0 with a 1 to 3% aqueous solution of a surfactant selected from the group consisting of dicarboxylic acids having C8 to C16 acyl groups and salts thereof, decanoylsarcosine and salts thereof, decanoylalanine and salts thereof, decanoic acid and salts thereof, lauryltrimethylammonium chloride, and combinations thereof, to obtain a solubilized solution of the protein;
• (2) adding the solubilized solution to a buffer with pH 6.5 to 9.0 comprising an additive selected from the group consisting of arginine, an arginine derivative, and combinations thereof, wherein said additive is at a concentration of 0.05 to 1.2 M, to lower the concentration of the surfactant to 0.02 to 0.5%, to obtain a mixture;
• and
• (3) recovering from the mixture the protein having a restored native higher-order structure.