Synthesis Of A Central Fragment Of The Carbohydrate Chains In The N-Linked Glycoproteins

The carbohydrate chains in the glycoproteins located on the surface of cells store enormous amount of biological information and play a great role in cellular recognition and adhesion. They may vary with the types, the specific period of differentiation, the functions and features of cells- An eminent change in carbohydrate chain structures in glycoproteins occurs and has featured in highly metastatic cancers an increase in the content of polylactosamine structures. Equally important is the observation that the increased polylactosamine biosynthesis accompanies the transition from benign to malignant phenotype in several human cell lines. For Asn-linked glycoproteins , polylactosamine chains are formed preferentially attached to 6-OH of the (1→6)-linked α-D-Man(see scheme I ). An inference was drawn by a cancer biologist that a central fragment of the complex carbohydrate chains in glycoproteins, say WXYZ, may have extensive biological functions. Used either in fundamental studies of cell biology and cancer cell biology or in clinic diagnosis and treatment of cancers by combining with peptides or proteins after its structural modification, the fragment is a necessity for the research in this field.In the period of my laboratory work, the chemical synthetic...