The characterization of the whey proteins of guinea-pig milk. The isolation and properties of alpha-lactalbumin.

1. The whey proteins of guinea-pig milk were examined by electrophoresis on paper, cellulose acetate, starch gel and polyacrylamide gel. 2. Two major proteins were detected, one of which was identified as blood serum albumin. 3. The major whey protein was isolated by CM-cellulose chromatography and on columns of Sephadex G-100. 4. The amino acid composition of the protein, taken in conjunction with its other properties, indicated that the major whey protein in guinea-pig milk is homologous with cow alpha-lactalbumin and that beta-lactoglobulin is absent from guinea-pig milk. 5. Guinea-pig alpha-lactalbumin, which was obtained crystalline, had mol.wt. 15800, N-terminal lysine and C-terminal glutamine.