Patent ID: 7244828

Claim:
A method of preparation of protein sample solution for analysis, wherein the protein sample solution contains one or more of non-protein agents selected from a group consisting of an anionic detergent, a cationic detergent, a non-ionic detergent, a zwitterionic detergent, a sulfobutane, a lipid, a polysaccharide, a polyphenol, a tannin, an alkaloid, a pigment, a reducing agent, a protein denaturant, an amine, HEPES, a TRIS buffer, and a salt, wherein after the preparation of the protein sample the protein in the sample is quantitatively recovered and is without interference from the non-protein agents originally present in the sample, comprises the following steps: (a) treating the protein sample solution with an acidic agent, and one or both agents selected from a group consisting of a salt and a precipitate-forming agent, wherein the treatment of the protein with the precipitate-forming agent follows the treatment of the protein sample solution with the acidic agent; (b) centrifuging the protein sample solution of the step (a) at least once to form a tight pellet at the bottom of the tube, remove and discard the supernatant and collect a protein pellet; (c) suspending and mixing the protein pellet of the step (b) at least once in at least one medium selected from a group consisting of a mixture of aqueous-organic solvent and an organic solvent; (d) centrifuging the protein pellet suspension of the step (c) and collect the protein pellet; and (e) suspending the protein pellet of the step (d) in a protein pellet solubilization reagent buffer, wherein the reagent buffer is provided with an acid neutralizing agent in a sufficient amount to substantially neutralize the acid captured in the protein pellet to facilitate a desired protein solubilization.