Structural analysis of oligosaccharide-alditols released by reductive beta-elimination from oviducal mucins of Bufo bufo: characterization of the carbohydrate sequence Gal(alpha1-3)GalNAc(alpha1-3)[Fuc(alpha1-2)]Gal.
Several tri- to hexasaccharide-alditols of the jelly coat surrounding the eggs of Bufo bufo were studied by methylation analysis, MALDI-TOF mass spectrometry, and 1H-NMR spectroscopy. As observed for six other amphibian species, these carbohydrate chains are highly species-specific. The main characteristics of the species Bufo bufo consists in the presence of the new carbohydrate sequence Gal(alpha1-3)GalNAc(alpha1-3)[Fuc(alpha1-2)]Gal, in which a blood group A determinant is substituted with an external alpha1-3 linked galactose unit. Since the role of carbohydrates appears more and more apparent during the fertilization processes, the species-specificity of these carbohydrate moieties should be relevant to the species-specific gamete recognition which characterizes most amphibians.
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