Department of Gastroenterology and Hepatology, Graduate School of Medicine , Hokkaido University , Sapporo 001-0021 , Japan.
Department of Advanced Clinical Glycobiology, Faculty of Medicine and Graduate School of Medicine , Hokkaido University , Sapporo 001-0021 , Japan.
Anal Chem. 2018 Nov 20;90(22):13193-13199. doi: 10.1021/acs.analchem.8b02775. Epub 2018 Oct 29.
Sialic acids occur widely as glycoconjugates at the nonreducing ends of glycans. Glycosphingolipids (GSLs) include a large number of sialyl-linked glycan isomers with α2,3-, α2,6-, and α2,8-linked polysialic acids. Thus, it is difficult to distinguish structural isomers with the same mass by mass spectrometry. The sialic acid linkage specific alkylamidation (SALSA) method has been developed for discriminating between α2,3- and α2,6-linked isomers, but sequential amidation of linkage-specific sialic acids is generally complicated and time-consuming. Moreover, analysis of GSL-glycans containing α2,8-linked polysialic acids using solid-phase SALSA has not been reported. Herein, we report a novel SALSA method focused on ring-opening aminolysis (aminolysis-SALSA), which shortens the reaction time and simplifies the experimental procedures. We demonstrate that aminolysis-SALSA can successfully distinguish serum GSL-glycan isomers by mass spectrometry. In addition, ring-opening aminolysis can easily be applied to amine and hydrazine derivatives.
唾液酸广泛存在于糖缀合物的非还原末端的聚糖中。糖鞘脂类（GSLs）包括大量的唾液酸化连接的聚糖异构体，具有α2,3-、α2,6-和α2,8-连接的多唾液酸。因此，很难通过质谱法区分具有相同质量的结构异构体。唾液酸键特异性烷基酰胺化（SALSA）方法已被开发用于区分α2,3-和α2,6-连接异构体，但连接特异性唾液酸的顺序酰胺化通常很复杂且耗时。此外，尚未有关于使用固相 SALSA 分析含有α2,8-连接的多唾液酸的 GSL-聚糖的报道。在此，我们报告了一种新型的 SALSA 方法，重点是开环氨解（氨解-SALSA），它缩短了反应时间并简化了实验步骤。我们证明了氨解-SALSA 可以通过质谱成功地区分血清 GSL-聚糖异构体。此外，开环氨解可以很容易地应用于胺和肼衍生物。
