02061naa a2200289 a 450000100080000000500110000800800410001902400510006010000160011124500760012726000090020352012610021265000180147365000110149165000090150265000180151165000180152965000180154765000270156565000210159265000100161365000170162365300240164065300240166470000160168877300670170421643632024-05-21       1979    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1017/S00220299000170272DOI1 aJOLLÈS, P.  aThe carbohydrate portions of milk glycoproteins.h[electronic resource]  c1979  ak-Casein is the main glycoprotein of cow's milk. Its polysaccharide part is O-glycosidically linked to threonine residue 133. It contains only 3 different sugars (Gal, GalNAc, NeuNAc), but a microheterogeneity has been detected at the sugar level. Two main polysaccharides have so far been characterized. The structure of the trisaccharide is NeuNAc α → 3 Gal β1 →3 GalNAc; the tetrasaccharide contains one additional sialic acid. The polysaccharide part of ovine k-casein resembles that of bovine k-casein, but contains also N-glycolyl neuraminic acid. Human k-casein contains 3 times more carbohydrate than bovine k-casein with 2 additional sugars, GlcNAc and Fuc. The various polysaccharide parts isolated from bovine colostrum k-caseinoglycopeptide are much more complex than those obtained from the normal glycopeptide, indicating an evolution of the sugar part as a function of time after parturition. Some aspects of the secondary structure of k-casein and the role of the sugar part are discussed. The carbohydrate moiety of another milk protein, human lactotransferrin, is also discussed briefly. It is comprised of 2 identical glycan groups, N-glycosidically linked to the protein, and quite different from the k-casein carbohydrate moiety.  aCarbohydrates  aCattle  aCows  aGlycoproteins  aMilk analysis  aMilk proteins  aMolecular conformation  aOligosaccharides  aSheep  aSialic acids  aAmino acid sequence  aSpecies specificity1 aFIAT, A. M.  tJournal of Dairy Researchgv. 46, n. 2, p. 187-191, Apr. 1979.