The Isolation and Identification of the B Protein of Lactose Synthetase as α-Lactalbumin

The B protein, a subunit of lactose synthetase (EC 2.4.1.c), was crystallized from bovine skim milk and bovine mammary tissue.The B protein was identified as cu-lactalbumin, based on the following criteria: substitution in the enxymic rate assays, spectra, immunological titrations, amino acid composition, mobility on starch gel electrophoresis, molecular weight, and cochromatography on diethylaminoethyl cellulose and Sephadex G-100.Thus the biological function of cr-ladalbumin is as a natural occurring subunit of lactose synthetase.