The structural basis of the different affinities of two types of acidic N -glycosidic glycopeptides for concanavalin a-sepharose

摘要: Affinity chromatography on lectins covalently bound to Sepharose has proved be a useful tool for the fractionation and purification of glycopeptides glycoproteins. The most commonly used lectin this purpose been concanavalin A. Studies binding oligosaccharides have indicated that at least two nonsubstituted or 2-O-substituted ol-mannosyl residues are required [l] . Recent reports from various source: ;oncanavaIin A-Sepharose shown in addition neutral mannose-rich glycopeptides, some acidic N-glycosidic by lectin, whereas others not [2-S]. Since carbohydrate composition both types is rather similar [3--S], reason difference affinity understood. present investigation was study structural basis separation ASepharose. Glycopeptides with known (or partially known) structures were chromatographed A fractions analyzed methylation. It found possessing peripheral NeuNAcGal-GlcNAc*-branches linked core pentasaccharide three branches (the these compounds below). different