Ganglioside-based neoglycoproteins

Nonspecific hydrophobic binding and membrane insertion limit the usefulness of radiolabeled gangliosides as high-affinity probes for carbohydrate-specific ganglioside receptors on cell membranes. To circumvent this limitation, the chapter discusses the synthesis of neoganglioproteins, which consists of gangliosides covalently linked, via the lipid moiety, to bovine serum albumin (BSA). Neoganglioproteins have the advantage of presenting the ganglioside determinants in a polyvalent array that may be important for high-affinity binding to complementary receptors. Ganglioside-protein conjugates are readily radiolabeled to high specific activity by standard protein radioiodination techniques allowing their use as radioligands to detect complementary ganglioside-bindging activities. Neoganglioprotein characterization involves determining the carbohydrate composition and structure and confirming the covalent nature of the carbohydrate–protein bond. Protein values are determined by any suitable protein microassay.