A CONVENIENT METHOD FOR PREPARATION OF IN DIVIDUAL OLIGOSACCHARIDE FRAGMENTS OF N-GLYCOPROTEINS FROM COMMON BEANS MAJOR STORAGE PROTEIN PHASEOLIN

A preparative method for isolation of N-linked oligosaccharides, fragm ents of phaseolin, which is a major storage protein of common beans (P haseolus vulgaris), was developed. Individual oligosaccharide-alditols Man(5-9)GlcNAc(1)GlcNAc-ol and Man(3)(Xyl)GlcNAc(1)GlcNAc-ol were obt ained after phaseolin degradation with LiBH4 or NaBH4-BaCl2 in aqueous tert-BuOH, the subsequent reduction with NaBH4, and HPLC. The main ca rbohydrate chain fragments of phaseolin [Man(9)GlcNAc(2), Man(7)GlcNAc (2), and Man,(Xyl)GlcNAc(2)] were also obtained in an unreduced form b y successive use of ion-exchange chromatography and HPLC. The oligosac charides were identified by means of their chromatographic behavior an d monosaccharide composition data, and their structures were confirmed by H-1 NMR.