Structural and Functional Diversity of Glycoconjugates: A Formidable Challenge to the Glycoanalyst

Glycoconjugates represent the most structurally and functionally diverse molecules in nature. They range in complexity from relatively simple glycosphingolipids and nuclear or cytosolic glycoproteins with dynamic monosaccharide modifications to extraordinarily complex mucins and proteoglycans (for review, see refs. 1 ,2 ). Some of the proteoglycans are perhaps the most complex molecules in biology, with more than 100 different saccharide side chains on a single polypeptide. We now realize that most proteins, even those within intracellular compartments, are co- and/or post-translationally modified by covalent attachment of saccharides (3 ).