High‐Resolution 1H‐NMR Spectroscopy of Free and Glycosidically Linked O‐ Acetylated Sialic Acids

作者：Johan Haverkamp, Herman van HALBEEK, Lambertus DORLAND, Johannes F.G. Vliegenthart, Reinhard Pfeil, Roland Schauer · 发表于：European Journal of Biochemistry · 年份：1982 · DOI：10.1111/j.1432-1033.1982.tb05881.x · 被引用次数：158 · 研究领域：Carbohydrate Chemistry and Synthesis、Glycosylation and Glycoproteins Research、Microbial Metabolites in Food Biotechnology

A number of naturally occurring and synthetic, partially O-acetylated derivatives of N-acetylneuraminic and N-glycoloylneuraminic acids have been investigated by 360-MHz 1H-NMR spectroscopy. O-Acetylation causes strong downfield shifts for the resonances of neighbouring sugar-skeleton protons. The chemical shifts of these resonances, together with their characteristic multiplet shapes, can be used for localisation of the position of O-acetyl substituents in the molecule. The number of such substituents in the molecule can be inferred from the number of acetyl-methyl singlets, which also have characteristic resonance positions. This method for determination of the number and position of O-acetyl substituents in sialic acid residues is very powerful for structural analysis of underivatized carbohydrate chains derived from glycoconjugates. This is demonstrated for the oligosaccharide N-acetyl-4-O-acetylneuraminosyl-(alpha 2 leads to 3)-lactose isolated from echidna milk.