Analysis of PA-oligosaccharides derived from Niigata K47 peptide by HPLC on an octadecylsilyl (ODS)-silica column. The Niigata peptide was double digested with glycopeptidase from almond and thermolysin to form the oligosaccharides. The oligosaccharides were purified by HPLC on a column of DEAE column and then subjected to aminopyridylation. The PA-oligosaccharides were injected to an ODS column for the identification by 3-dimensional mapping technique. From the 3-D elution mapping chart, the Niigata K47 peptide was found to contain 2 kinds of biantennary neutral oligosaccharides (Neutral-a and Neutral-b) and biantennary sialyl oligosaccharides (Mono-S and Di-S), respectively.