Structural studies on the carbohydrate portion of human antithrombin III

Human antithrombin III has been shown to contain four identical N-glycosidically linked carbohydrate chain per molecule. These carbohydrate chains have been investigated by sugar and methylation analysis before and after removal of N-acetylneuraminic acid residues. The chains have been further investigated by Smith degradation, trifluoroacetolytic degradation, and degradation after chromium trioxide oxidation. As a result of these studies, the following structures is proposed for the carbohydrate chains in human antithrombin III: (formula: see text). NeuNAc, N-acetylneuraminic acid; Galp, galactopyranose; GlcNAcp, 2-acetamido-2-deoxyglucopyranose; Manp, mannopyranose are the abbreviations used in the structure.