A new hexasaccharide chain isolated from bovine colostrum kappa-casein taken at the time of parturition.

The carbohydrate units linked to caseinoglycopeptide from colostrum taken 30 min after parturition were released as reduced oligosaccharides by alkaline borohydride treatment, and separated into four acidic oligosacchariditols (a hexa- (11.0%), penta- (38.5%), tetra- (35.5%) and a trisacchariditol (15.0%)). Structural studies showed that the hexasacchariditol was a new structure and had the chemical structure: NeuNAc-alpha-2-3-Gal-beta-1-3-[NeuNAc-alpha-2-3-Gal- beta-1-4-GlcNAc-beta-1-6-]-N-acetylgalactosaminitol(GalNAcItol). The other three oligosacchariditols were shown to be NeuNAc-alpha-2-3-Gal-beta-1-3-[Gal-beta-1-4-GlcNAc-beta-1-6-]-GalNAcItol, NeuNAc-alpha-2-3-Gal-beta-1-3-[NeuNAc-alpha-2-6-]-GalNAcItol and NeuNAc-alpha-2-3-Gal-beta-1-3-GalNAcItol, which were identical with those found previously in colostrum kappa-casein taken 6 h after parturition.