Analysis of Glycoconjugate Saccharides in Organelles Isolated from Castor Bean Endosperm

The presence of lipid- and protein-bound sugars in the major organelle fractions isolated from germinating castor bean (Ricinus communis L.) endosperm has been established. Microsomes, glyoxysomes and mitochondria were subfractionated into a membrane fraction and a fraction containing peripheral membrane and soluble matrix proteins. The membranes were further subfractionated into monosaccharide lipid, oligosaccharide lipid and lipid-free protein components. The constituent sugars present in the prepared fractions were released and identified by gas-liquid chromatography. While all derived protein fractions contained the N-acetylglucosamine and mannose typically found in the inner core region attached to asparagine residues in many glycoproteins, some differences were noted in the organellar distribution of peripheral sugars such as fucose, arabinose, and xylose.