Stability studies of hydrazide and hydroxylamine-based glycoconjugates in aqueous solution |
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Authors: | Anna V Gudmundsdottir |
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Institution: | Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, Canada |
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Abstract: | Glycoconjugates can be readily formed by the condensation of a free-reducing terminus and a strong α-effect nucleophile, such as a hydrazide or a hydroxylamine. Further characterization of a series of glycoconjugates formed from xylose, glucose and N-acetylglucosamine, and either p-toluenesulfonyl hydrazide or an N-methylhydroxylamine, was carried out to gain insight into the optimal conditions for the formation of these useful conjugates, and their stability. Their apparent association constants (9-74 M−1) at pH 4.5; as well, as rate constants for hydrolysis, at pH 4.0, 5.0 and 6.0 (37 °C), were determined. The half-lives of the conjugates varied between 3 h and 300 days. All the compounds were increasingly stable as the pH approached neutrality. Conjugate hydrolysis rates mirrored those found for O-glycoside hydrolysis where conjugates formed from electron-rich monosaccharides hydrolyzed more rapidly. |
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Keywords: | Glycoconjugate Glycosylhydrazides Oligosaccharide labelling Hydrolysis rates |
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