Matrix-assisted laser desorption/ionization mass spectrometry of neutral and acidic oligosaccharides with collision-induced dissociation

Using ribonuclease B and human alpha(1)-acid glycoprotein (AGP) as model gl ycoproteins, matrix-assisted laser desorption/ionization (MALDI) mass spect rometry with collision-induced dissociation (CID) is validated here as an e ffective tool for oligosaccharide sequencing. The spectra acquired for high -mannose and complex oligosaccharide structures show characteristic fragmen ts resulting from cleavages of the glycosidic bonds and a few cross-ring cl eavages. Esterification of the sialic acid residues is essential in stabili zing the acidic N-linked oligosaccharides. An important analytical feature observed in all acquired spectra is the occurrence of cleavages on the same antenna up to the branching point, as deduced from the absence of fragment ation due to the simultaneous cleavages on two or more antennas. (C) 1998 E lsevier Science Ltd. All rights reserved.