Provided are: a protein complex capable of selectively and asymmetrically oxidizing an enantiomer of a secondary alcohol without adding a coenzyme and having an asymmetric oxidation activity in a water-soluble solvent system in the presence of oxygen a method for producing the same and a method for coating the protein complex with a high molecular weight compound. The method for producing the protein complex includes: (1) enclosing a crude water-soluble protein in a gel, air-oxidizing the gel, and eluting the protein complex into an aqueous solution and (2) applying gravity to concentrate and precipitate the protein complex, redissolving the precipitate in an aqueous glycine sodium hydroxide solution of about 0.5 mM and allowing the same to homogeneously coexist with a high molecular weight compound, and re-precipitating the solution and dehydrating and drying the same to yield a protein complex coated with a high molecular weight compound.
