The pyridylamination method was originally described in 1978 as a means of analyzing glycan structures with high-sensitivity. Subsequently, the method has been applied to structure analyses of glycans including glycosidase digestion, 2D-mapping by various kinds of HPLC's, partial acetolysis, Smith degradation, methylation analysis, nuclear magnetic resonance, mass spectrometry, and affinity assay for lectins. Glycans on glycoconjugates are liberated by hydrazinolysis followed by N-acetylation. Reducing ends of the released glycans are tagged with 2-aminopyridine by reductive amination. Pyridylamino (PA-) derivatives of glycans with fluorescence and a positive charge have the following advantages: 1. high sensitivity in detection; 2. excellent separation in reversed phase HPLC; 3. high chemical stability under the conditions for structure elucidation; 4. applicable to many authentic methods for glycan analysis.
