Isolation, composition and functional properties of alpha-lactalbumins from several species

1. Galactosyltranferases were isolated from bovine and pig milk and alpha-labtalbumins from milks of cow, pig, dog, rabbit, baboon and chimpanzee. 2. Alpha-Lactalbumins were characterized by gel electrophoresis, amino acid composition, ultraviolet absorbance, and ability to promote synthesis of lactose by the galactosyltransferases. 3. The order of K-m values of the various alpha-lactalbumins was the same with both cow and pig galactosyltransferases and differed from the order predicted from taxonomical classification of the species. 4. A280/A260 abosrbance ratios were correlated with K-m values suggesting involvement of tyrosyl groups in the function of alpha-lactalbumin.