Primary structure of the glycans from mouse serum and milk transferrins.
A 'serotransferrin-like' protein was purified from mouse milk. This serotransferrin cross-reacts immunologically with the serotransferrin isolated from mouse plasma and not with the mouse lactotransferrin (lactoferrin). Sugar analysis of the three transferrins, i.e. serotransferrin, milk 'serotransferrin-like' protein and lactotransferrin, revealed that the major difference between the glycan primary structure of mouse serotransferrin and those of mouse milk 'serotransferrin-like' protein and lactotransferrin concerns essentially the presence of one fucose residue in the last two proteins. For structural determination, the N-glycosidically linked glycans were released from the protein by a reductive cleavage of the oligosaccharide-protein linkage under strong alkaline conditions. The primary structure of the released oligosaccharide alditols was determined by methylation analysis and 400 MHz 1H-n.m.r. spectroscopy. The oligosaccharide alditols released from milk 'serotransferrin-like' protein and lactotransferrin were identical and were identified as disialylated biantennary glycans of the N-acetyl-lactosamine type with a fucose residue alpha-1,6-linked to the N-acetylglucosamine residue conjugated to the peptide chain and having the following primary structure: NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc(beta 1-2)Man(alpha 1-3)[NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc(beta 1-2)Man(alpha 1-6)]Man(beta 1-4)GlcNAc(beta 1-4)[Fuc(alpha 1-6)]GlcNAc(beta 1-N)Asn. The serotransferrin glycan has the same primary structure but is only partially fucosylated (10-15%).
D000818:Animals; D002240:Carbohydrate Sequence; D002853:Chromatography, Liquid; D005779:Immunodiffusion; D007781:Lactoferrin; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D051379:Mice; D008892:Milk / Q000032:analysis*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis; D010455:Peptides / Q000032:analysis; D011134:Polysaccharides / Q000032:analysis*; D013402:Sugar Alcohols / Q000032:analysis; D014168:Transferrin / Q000302:isolation & purification
D009844:Oligosaccharides; D010455:Peptides; D011134:Polysaccharides; D013402:Sugar Alcohols; D014168:Transferrin; D007781:Lactoferrin