SIALYLLACTOSE OCCURS AS FREE LACTONES IN-OVINE COLOSTRUM

Three sialyl oligosaccharide fractions were separated from ovine colos trum by gel filtration, anion exchange chromatography and normal-phase HPLC. They were characterized by H-1-NMR spectrometry as follows: Neu 5Ac alpha 2-->3Gal beta 1-->4Glc, Neu5Gc alpha 2-->6Gal beta 1-->4Glc and three forms of Neu5Gc alpha 2-->3Gal beta 1-->4Glc, namely Neu5Gc alpha 2-->3Gal beta 1-->4Glc itself, its lactone derivative between th e carboxyl group of Neu5Gc and Gal OH-2 and another lactone derivative between the carboxyl group and Gal OH-4. In this study, Neu5Gc-lactos e lactones, in their free form, have been isolated for the first time from any natural sources including milk or colostrum. (C) 1998 Elsevie r Science B.V. All rights reserved.