Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Clúster Científico y Tecnológico Biomimic®, Instituto de Ecología A. C., Carretera antigua a Coatepec No. 351, Colonia El Haya, Xalapa, Veracruz, 91070, Mexico.
Unidad de Servicios de Apoyo en Resolución Analítica, Universidad Veracruzana, Apartado Postal 575, Xalapa, Veracruz, 91190, Mexico.
Carbohydr Res. 2020 Apr;490:107952. doi: 10.1016/j.carres.2020.107952. Epub 2020 Feb 13.
The major anomer of non-protonated neutral d-glucosamine GlcN is the β-form, while the α-anomer is dominant for protonated cationic glucosamine GlcNH. The present work confirmed correlation between the anomerization and the protonation by simultaneous determination of signal intensity and chemical shift in pD-variation H NMR, and formulated the equilibrium constants between subspecies α-GlcN, β-GlcN, α-GlcND, and β-GlcND to interpret the correlation. The individual anomerization constants, K = [βGlcN]/[αGlcN] and K = [βGlcND]/[αGlcND], are linked to each other through the relation K∙K = K∙K with the deuteration constants K and K of the anomers. The anomer populations are stimulated by OD and D ions in the dose-response form. The acidic deuteron in α-GlcND is populated mostly at the nitrogen atom, whereas the population in β-GlcND is comparable at nitrogen and anomeric oxygen; this difference is consistent with the basicity of the nitrogen and the anomerization process of glucosamine.
未质子化中性 D-葡萄糖胺 GlcN 的主要异头物为β型，而质子化阳离子葡萄糖胺 GlcNH 的α-异头物占优势。本工作通过 pD 变化~1H NMR 中信号强度和化学位移的同时测定，证实了异头化和质子化之间的相关性，并制定了α-GlcN、β-GlcN、α-GlcND 和β-GlcND 各亚物种之间的平衡常数，以解释这种相关性。各个异头物常数 K=[βGlcN]/[αGlcN]和 K=[βGlcND]/[αGlcND]通过常数 K 和 K 的关系 K·K=K·K 相互关联，其中 K 和 K 为异头物的氘化常数。OD 和 D 离子以剂量反应的形式刺激异头物的分布。α-GlcND 中的酸性氘原子主要位于氮原子上，而β-GlcND 中的氘原子在氮原子和异头氧原子上的分布相当；这种差异与氮原子的碱性和葡萄糖胺的异头化过程一致。
