A 360-MHz 1H-NMR study of three oligosaccharides isolated from cow kappa-casein.

360-MHz 1H-NMR spectra were recorded of NeuAc alpha(2 leads to 3)Gal beta (1 leads to 3)GalNAc-ol (I), Gal beta(1 leads to 3)[NeuAc alpha(2 leads to 6)] GalNAc-ol (II) and NeuAc alpha (2 leads to 3)-Gal beta(1 leads to 3) [NeuAc alpha(2 leads to 6)]GalNAc-ol (III). The chemical shifts and coupling constants of the anomeric protons, the H-3ax and H-3eq of NeuAc, the GalNAc-ol skeleton protons, the H-3 of Gal and the N-acetyl protons of GalNAc-ol and NeuAc provide conclusive evidence for the identification of the primary structures. Compound II represents a novel carbohydrate chain of kappa-casein.