Separation of Major Casein Fractions Using Cation-Exchange Fast Protein Liquid Chromatography

Abstract

Whole casein was separated into β-casein, κ-casein, αs1-casein, and αs2-casein fractions using cation-exchange fast protein liquid chromatography. The γ-caseins and several unidentified peaks were also separated. A urea-acetate buffer at pH 5 and a NaCl gradient from 0 to .26 M were used to separate the casein fractions. Several γ-caseins and unidentified fractions eluted first, followed by three β-casein peaks, several γ-casein and unidentified peaks, κ-casein, αs1-casein, and αs2-casein. Some γ-caseins eluted with β-casein. The four major caseins, which accounted for over 90% of the whole casein fractions, were accounted for with this method, and the calculated compositions correlated well with values obtained using anion-exchange fast protein liquid chromatography at pH 7.