Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
Anal Chem. 2018 Feb 6;90(3):1525-1530. doi: 10.1021/acs.analchem.7b03735. Epub 2018 Jan 24.
Saccharide isomer differentiation has been a challenge in glycomics, as the lack of technology to decipher fully the diverse structures of compositions, linkages, and anomeric configurations. Several mass spectrometry-based methods have been applied to the discrimination of disaccharide isomers, but limited quantitative analyses have been reported. In the present study, MALDI-LIFT-TOF/TOF has been investigated to differentiate and relatively quantify underivatized glucose-containing disaccharide isomers that differ in composition, connectivity or configuration. N-(1-naphthyl)ethylenediamine dihydrochloride (NEDC) was used as a highly sensitive matrix without matrix interferences in low mass range, thus yielding intense chloride-attached disaccharide ions [M + Cl], which could be fragmented to give diagnostic characteristic fragment patterns for distinguishing these isomers. Three different types of disaccharide isomers were successfully relatively quantified in a binary mixture using the specific product ion pairs. Finally, this method was utilized to identify and relatively quantify two disaccharide isomers in Medicago leaf (maltose and sucrose) without numerous preparation steps. In general, this method is a fast, effective, and robust method for rapid differentiation and quantitation of disaccharide isomers in complex medium.
糖的差向异构体的区分一直是糖组学的一个挑战，因为缺乏技术来完全解析组成、键合和端基构型的各种结构。已经应用了几种基于质谱的方法来区分二糖异构体，但报道的定量分析有限。在本研究中，MALDI-LIFT-TOF/TOF 已被用于区分和相对定量未经衍生化的含有葡萄糖的二糖异构体，这些异构体在组成、连接或构型上存在差异。N-(1-萘基)乙二胺二盐酸盐 (NEDC) 被用作一种高度灵敏的基质，在低质量范围内没有基质干扰，从而产生强烈的氯连接的二糖离子 [M + Cl]，可以对其进行碎裂，从而得到用于区分这些异构体的特征性片段模式。使用特定的产物离子对，成功地在二元混合物中相对定量了三种不同类型的二糖异构体。最后，该方法用于鉴定和相对定量 Medicago 叶中的两种二糖异构体（麦芽糖和蔗糖），而无需进行许多准备步骤。总的来说，该方法是一种快速、有效和强大的方法，用于快速区分和定量复杂介质中的二糖异构体。
