Isolation and Amino Acid Composition of Human Milk Casein and its Components

A modified procedure is described for isolation of whole human milk casein. Human milk casein has been separated into three fractions. The gamma fraction was found to be more abundant than the beta-fraction, while the alpha-fraction occurred only in tracer amount. The amino acid composition, electrophoretic mobilities, and the side chain groups of the human milk casein and its fractions have been determined.