以碰撞誘導解離串聯質譜法的邏輯程序應用於低聚半乳糖的結構鑑定

Abstract

醣由數個單醣（Monosaccharides）組成，單醣與單醣間，以糖苷鍵（Glycosidic Bond）鍵結，形成高度複雜的結構。若想更進一步了解醣在這些生物系統中扮演的角色，就須要知道這些糖苷鍵如何鍵結。到目前為止，已經發展各種不同解醣結構的方法，但仍然沒有一個方法能快速且準確的解出每一個醣的結構。因此，本研究利用高效液相層析法（High-Performance Liquid Chromatography, HPLC）及質譜分析法（Mass Spectrometry）建立這個雙醣質譜的資料庫，並以醣解離機制的原理，建立解離順序，再藉由碰撞誘導解離（Collision-Induced Dissociation, CID）將寡醣分解成數個雙醣（Disaccharides）碎片，並將這些雙醣碎片的質譜（Mass Spectra）分別與我們建立的雙醣質譜的資料庫進行比對，快速的鑑定醣的結構。本研究使用幾個已知的寡醣作為例子，藉由此次提出的方法，解出這些寡醣的結構。 Carbohydrates are closely related to everyone life. It can be found in foods, blood, organisms, plants, bacteria, and so on. They are composed of different numbers of monosaccharides and present in various structures. Understanding these structures further assists the research of carbohydrate in biological systems. By now, many methods have been proposed to identify the structure of oligosaccharides. It is still challenging for these methods to resolve the structures in detail. In this study, a new rapid method that can identify the structure of oligosaccharides was demonstrated. This method was based on the comparison of disaccharide database with the spectra of disaccharides residues dissociated from oligosaccharide by collision-induced dissociation (CID). The disaccharides database was built using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MSn) and the spectra of disaccharide residues produced from CID of oligosaccharides were obtained by ESI-MSn. A logical procedure according to the dissociation mechanism was used to determine the sequence of tandem MS. This new method was applied to identify the oligosaccharides structures, including linkage positions, anomeric configurations, and branch locations. Here, several underived oligosaccharides with sodium ion adducts were used as examples to demonstrate this new method.