The isolation of glyco-alpha-lactalbumins from some ruminant milks
Prieels, J.P.; Cludts, M.; Dolmans, M.; Léonis, J.
Archives Internationales de Physiologie et de Biochimie 82(1): 194
1974
ISSN/ISBN: 0003-9799 PMID: 4137279 Document Number: 74969
Bovine, caprine and ovine alpha -lactalbumins were purified by (NH4)2SO4 fractionation, gel filtration on Sephadex G-75 and ion-exchange chromatography on DEAE-Sephadex A-25 with elution on a salt gradient (0-3 M NaCl). Glycosylated components, as evidenced by the phenol-sulphuric acid reaction, appeared as discrete peaks before and after the main peak of non-glycosylated protein. Amino acid analysis revealed no differences between glycosylated and corresponding non-glycosylated components within the milk of each of the 3 species. Further, there were no differences between the glycosylated and non-glycosylated components in circular dichroism spectra or apparent Km and Vmax for binding with the A protein of lactose synthetase. Preliminary analysis of the major glycosylated component of bovine milk indicated that the glycosidic chain is covalently attached to Asn45 or Asn46.