Structural analysis of N-glycans of storage glycoproteins in soybean (Glycine max. L) seed

The structures of N-linked sugar chains (N-glycans) of storage glycoproteins in soybean seeds have been identified. Eight pyridylaminated (PA-) N-linked sugar chains were derived and purified from hydrazinolysates of the storage glycoproteins by reverse-phase HPLC and size-fractionation HPLC. The structures of the PA-sugar chains purified were first identified by two-dimensional PA-sugar chain mapping and ion-spray mass analysis, considering the results of sugar composition analysis or sequential exoglycosidase digestion. The deduced structures were further analyzed by ion-spray tandem mass spectrometry and 500MHz H-1-NMR spectrometry. The eight structures fell into two categories; the major class (96.6%) was a typical high mannose-type, the minor class was a xylose containing-type (Man(3)Xyl(1), GlcNAc(2), Man(3)Fuc(1)Xyl(1)GlcNAc(2); 3.4%).