Preparation and fractionation of goat κ-casein: analysis of the glycan and peptide components

Abstract

SummaryWhole goat κ-casein was prepared by chromatography of whole casein on hydroxyapatite. Chromatography of whole κ-casein on DEAE-cellulose separated 5 fractions. All of them were sensitive to chymosin. Their amino acid and carbohydrate composition, phosphate content and molecular weight were determined. Galactose,N-acetylgalactosamine,N-acetyl andN-glycolyl neuraminic acids were identified in whole κ-casein. It appears that goat κ-casein, like cow, buffalo and ewe κ-caseins, is composed of several fractions having identical peptide chains and differing in their carbohydrate contents. The main fraction, devoid of carbohydrate, was treated with chymosin. The para-κ-casein and caseinomacropeptide were isolated. Their amino acid composition and phosphate content were determined.