Primary structure of rabbit alpha-lactalbumin.

Rabbit alpha-lactalbumin was purified from the milk of New Zealand White rabbits. It was found to exist predominantly as a glycoprotein, containing 5 mol of glucosamine per mol of protein, as well as other sugars. The amino acid sequence of the protein was determined by sequenator analysis and carboxypeptidase digestion. There are 122 amino acids in the protein and a single carbohydrate moiety, probably attached to an asparagine residue at position 45. The C terminus of rabbit alpha-lactalbumin is one residue shorter than that of the other alpha-lactalbumins. Sequence comparisons indicate that the alpha-lactalbumin gene has been undergoing more frequent mutation than had previously been thought. A new method of preparative peptide mapping using 2,5-diphenyloxazole (PPO) fluor to detect peptides is described.