PURPOSE: To enable the subject ready and economic purification by adding a reduced concentration of a protein modifier to a prescribed reduced form human lysozyme solution and also keeping its pH acidic.
CONSTITUTION: Microorganisms transformed by a vector containing DNA coding human lysozyme are cultured and a protein modifier of 4-6M such as guanidine hydrochloride and a reducing agent of 0.0051.0M such as 2-mercaptoethanol are added to the resultant human lysozyme-containing solution to obtain a reduced form human lysozyme solution (A). The resultant solution (A) is then diluted using water or a buffer solution, etc., so that the concentration of the protein modifier may be reduced to (1/3)(1/2) of that at a time of solubilization treatment, e.g. from 6 M to 2-3M. Contaminated proteins are precipitated by treating the diluted solution at 0-4°C for 1-24 hr in a state where the concentration of protein and pH of the solution are respectively 0.5-3.0 mg/ml and 2-3 to obtain a mixture solution (B). The above-obtained solution (B) is subjected to centrifugal separation, etc., to remove the precipitate, thus purifying the objective reduced form human lysozyme.
KUMAGAI KAZUO
KONO EMIKO
