Affinity mass spectrometry using selective and pressure-enhanced proteolytic excision and extraction combined with MALDI and ESI-MS has been applied to the identification of epitope binding sites of GalNac and blood group oligosaccharides in lectins. The epitope peptides identified comprise all essential amino acids involved in carbohydrate recognition, in complete agreement with available X-ray structures. Coupling of a specific peptide glycoprobe to the gold surface of a biosensor chip was successfully employed for identification of carbohydrate epitopes and affinity measurements.<eng>
