Identification of canine alpha-lactalbumin

The nucleotide sequence of canine alpha-lactalbumin cDNA from canine mammary tissue was determined by polymerase chain reaction with degenerate primers. A 742 base pairs nucleotide sequence cloned was similar to the size of mRNA in Northern blot analysis. The cDNA encodes 142 amino acid residues containing the conserved sequence motif of alpha-lactalbumin, demonstrating the highest homology with pig (73% identity-82% similarity) among the known amino acid sequences of alpha-lactalbumin. The canine cDNA also showed 71% identity-78% similarity with human, 58-73% with mouse, 60-74% with rat, 67-77% with goat, 66-77% with cattle, and 67-76% with sheep, respectively.