Chromatograms and Mass Spectra of High-Mannose and Paucimannose -Glycans for Rapid Isomeric Identifications.

-Linked glycosylation is one of the most essential post-translational modifications of proteins. However, -glycan structural determination remains challenging because of the small differences in structures between isomers. In this study, we constructed a database containing collision-induced dissociation MS mass spectra and chromatograms of high-performance liquid chromatography for the rapid identification of high-mannose and paucimannose -glycan isomers. These -glycans include isomers by breaking of arbitrary numbers of glycosidic bonds at arbitrary positions of canonical ManGlcNAc -glycans. In addition, some GlcManGlcNAc -glycan isomers were included in the database. This database is particularly useful for the identification of the -glycans not in conventional -glycan standards. This study demonstrated the application of the database to structural assignment for high-mannose -glycans extracted from bovine whey proteins, soybean proteins, human mammary epithelial cells, and human breast carcinoma cells. We found many -glycans that are not expected to be generated by conventional biosynthetic pathways of multicellular eukaryotes.