Abstract
In proteomics research field, identification of proteins was performed by a combining method of mass spectrometry data and genome and DNA sequence database. This is an elegant method but it is not enough to analyze the functions of the proteins perfectly. It is essential to analyze post-translational modifications of the proteins to understand their functions in a cell. Glycosylation is one of the most important factors controlling the functions of the proteins, so a new technique of glycosylation analysis has been desired. Until now, it is difficult to perform the structure analysis of glycosylation by only mass spectrometry, because the structures of glycosylation are very complex and they have a lot of structure isomers. Post-source decay (PSD) spectra of glycosylation and oligosaccharides show the sequence of the sugar residues. PSD method is helpful to analyze their structures but the structural isomers can not be distinguished. So, we have been studying the relative abundance of the PSD ions in the MALDI-PSD spectra of oligosaccharides. Comparing the PSD spectra of the isomers, we found that their ion abundances differed. Thus, we can distinguish between the isomers of oligosacchairdes. There are general rules between the abundance of the PSD ions and the structures of the isomeric oligosaccharides.
