Mass Spectrometric Analysis of Highly Acidic Polysaccharides
Glycosaminoglycans (GAGs) are a class of highly acidic polysaccharides that are found in the extracellular matrix and in proteoglycans, which are cell membrane-bound proteins that are post-translationally modified with GAGs (1, 2). Analysis of these compounds by classical methods has been difficult due to the heterogeneous and polyanionic nature of GAGs. However, by mixing GAG oligosaccharides with basic peptides to form a noncovalent complex, it is possible to accurately determine their molecular weight using matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) (3, 4). Such molecular weight measurements provide information on the length of the carbohydrate chain and the degree of sulfation. In addition, mass spectrometric measurements on enzymatic and chemical degradation products of isolated compounds may yield the entire structure of the analyte of interest. Figure 5.1 represents the structure of a heparin fragment.
KeywordsCaffeic Acid Noncovalent Complex Acidic Polysaccharide Lower Laser Intensity Basic Peptide
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