An automated interpretation of MALDI/TOF postsource decay spectra of oligosaccharides. 1. Automated peak assignment.

A computer program has been developed that helps the interpretation of MALDI/TOF postsource decay (PSD) spectra of N-linked oligosaccharides of a protein. The program includes routines for automated peak assignment and generation of a simulated PSD spectrum. From a raw spectrum, peaks are assigned automatically; i.e., numbers of saccharide residues removed from the parent ion are calculated. If the structure of the oligosaccharide is known, a simulated PSD spectrum of the oligosaccharide will be generated. The simulated PSD spectrum helps interpretation of the observed spectrum. While, in a case where several candidate structures are given, one can narrow the field of plausible structures for the unknown oligosaccharide by comparing the observed spectrum with the simulated PSD spectra. Using a Pentium 233-MHz microprocessor, it takes only a few seconds to interpret a spectrum.