Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2007–2008

Abstract

This review is the fifth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2008. The first section of the review covers fundamental studies, fragmentation of carbohydrate ions, use of derivatives and new software developments for analysis of carbohydrate spectra. Among newer areas of method development are glycan arrays, MALDI imaging and the use of ion mobility spectrometry. The second section of the review discusses applications of MALDI MS to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N- and O-linked glycans from glycoproteins, biopharmaceuticals, glycated proteins, glycolipids, glycosides and various other natural products. There is a short section on the use of MALDI mass spectrometry for the study of enzymes involved in glycan processing and a section on the use of MALDI MS to monitor products of the chemical synthesis of carbohydrates with emphasis on carbohydrate-protein complexes and glycodendrimers. Corresponding analyses by electrospray ionization now appear to outnumber those performed by MALDI and the amount of literature makes a comprehensive review on this technique impractical. However, most of the work relating to sample preparation and glycan synthesis is equally relevant to electrospray and, consequently, those proposing analyses by electrospray should also find material in this review of interest.

Biomarker Characterization by MALDI–TOF/MS

“…Figure 2 shows the schematic diagrams of MALDI-TOF/MS analysis. Conventionally, MALDI-TOF/MS combined with two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) has been the main analytical method for identifying proteins in bottom-up proteomics [123][124][125]. In clinical proteomics, this approach has been used to evaluate the expression of specific proteins or peptides in biological samples between controls and patients [126][127][128].…”

Quantitative Approach for Small Molecules Using Laser Desorption/Ionization Mass Spectrometry

“…4,5) The observed highly reproducible MALDI spectra were explained as a result of a uniform crystal layer. 6) Since the operation is simple and readily feasible, the approach would be of further utility and applicability for a variety of target molecules. In addition, the results may encourage researchers to seek the best measurement conditions using MALDI-MS.…”

Mass spectrometry-based N-glycoproteomics for cancer biomarker discovery

“…The heterogeneous characteristic of glycosylated-peptide complicates the corresponding MS analysis and therefore promotes different ionization experimental conditions for different samples. For example, neutral and basic glycosylated-peptides may be analyzed under positively charged ions mode, while acidic glycoconjugates (sialic acid and sulfate containing) tend to be detected more effectively as negatively charged [50]. …”