Analysis of Carbohydrates and Glycoconjugates by Matrix‐assisted Laser Desorption/Ionization Mass Spectrometry: An Update for 2015–2016

Abstract

This review is the ninth update of the original article published in 1999 on the application of matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo‐ and poly‐saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Electrospray ionization in‐source decay of N‐glycans and the effects on N‐glycan structural identification

“…[26][27][28][29][30][31] Carbohydrate is another group of non-volatile and thermally unstable molecules for which ESI and MALDI are widely used in MS for ionization. [32][33][34] N-Glycan is one major component of carbohydrate; it plays an important role in post-translational modifications of proteins. Most small N-glycan ions generated by ESI are singly charged, but doubly charged ions start to dominate as the size of the N-glycans increases.…”

“…Carbohydrate is another group of non‐volatile and thermally unstable molecules for which ESI and MALDI are widely used in MS for ionization 32–34 . N ‐Glycan is one major component of carbohydrate; it plays an important role in post‐translational modifications of proteins.…”

Formation and fragmentation of doubly and triply charged ions in the negative ion spectra of neutral N-glycans from viral and other glycoproteins

“…Many methods have been used to determine the structures of these glycans (see, for example, [ 3 – 13 ]). Early studies by mass spectrometry relied on combined gas chromatography/mass spectrometry (GC/MS) and fast atom bombardment (FAB) [ 14 ] ionization but most studies now use matrix-assisted laser desorption/ionization (MALDI, see Harvey [ 15 ] and reviews cited therein) or electrospray ionization (ESI), the latter method being conveniently interfaced with high-performance liquid chromatography (HPLC). A potential problem with ESI is the preferential production of ions in several charge states, thus inhibiting acquisition of a quantitative glycan profile from mixtures.…”

“…They play essential roles in areas such as cell-cell recognition, glycoprotein folding, protection from immune recognition, fertilization, and reproduction [1]. Broadly speaking, these compounds can be divided into three types (Scheme 1) depending on the glycan chains that are attached to the common trimannosyl-N,N'-di-acetyl-chitobiose core: High mannose glycans 1-10 and 13 (Scheme 1) where three chains consist of mannose residues, sometimes with one capped with up to three glucose residues (1)(2)(3)(4), hybrid glycans such as 11 and 12 that contain a mixture of mannose and GlcNAc-Gal (or GalNAc) chains and complex glycans (e.g., [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] where all mannose residues, except those in the core, are replaced with similar GlcNAc-Gal chains. Many of these chains can be capped with acid groups such as N-acetyl-(or N-glycolyl)neuraminic acid, sulfate, or phosphate groups or can be extended by the addition of additional Gal-GlcNAc moieties.…”

“…Many methods have been used to determine the structures of these glycans (see, for example, [3][4][5][6][7][8][9][10][11][12][13]). Early studies by mass spectrometry relied on combined gas chromatography/ mass spectrometry (GC/MS) and fast atom bombardment (FAB) [14] ionization but most studies now use matrixassisted laser desorption/ionization (MALDI, see Harvey [15] and reviews cited therein) or electrospray ionization Published in the topical collection Analytical Characterization of Viruses with guest editor Joseph Zaia.…”