Targeted use of exoglycosidase digestion for the structural elucidation ofneutral O-linked oligosaccharides

Exoglycosidase digestion in combination with the catalog-library approach ( CLA) is used with matrix-assisted laser desorption/ionization Fourier trans form mass spectrometry (MALDI-FTMS) to obtain the complete structure of oli gosaccharides. The CLA is a collision-induced dissociation (CID)-based meth od used to determine the structure of O-linked neutral oligosaccharides. It provides both linkage and stereochemical information. Exoglycosidases are used to confirm independently the validity of the CLA. In some cases, the C LA provides structural information on all but a single residue. Exoglycosid ase is used to refine these structures. In this way, exoglycosidase use is targeted employing only a small number of enzymes. Exoglycosidase arrays, w hich have been used with N-linked oligosaccharides, is avoided despite the larger variations in structures of O-linked species. (C) 2001 American Soci ety for Mass Spectrometry.