Amino acid composition of β-caseins from the milks of Bos indicus and Bos taurus cows: A comparative study

1. β-Caseins B (Bos taurus), BZ and D (Bos indicus) were examined for amino acid composition. 2. BZ differs from B in content of several neutral amino acids and possibly glutamic acid, as well as in tryptic “fingerprints”. 3. β-D differs from BZ notably in content of arginine (+1), lysine (+1) and histidine (−1), but also in one additional residue each of threonine, serine and alanine. 4. β-D (like β-C, Bos taurus) lacks 1–2 residues of phosphorus as compared with B. 5. It is likely that β-C (Bos taurus), itself, occurs as polymorphs.