BIOTINYLATED DIAMINOPYRIDINE - AN APPROACH TO TAGGING OLIGOSACCHARIDES AND EXPLORING THEIR BIOLOGY

Fluorescent tagging of free oligosaccharides by reductive amination pe rmits sensitive detection and fractionation of these molecules. To exp and the scope of this approach, we have synthesized a fluorescent reag ent, 2-amino-(6-amidobiotinyl)pyridine. This reagent can tag oligosacc harides under nondegradative conditions with high efficiency. The resu lting adducts show excellent fractionation by reverse-phase HPLC with sensitive detection in the low picomole range. When combined with sequ ential exoglycosidase digestion, step-wise sequencing of the sugar cha ins is possible. The biotinyl group can also be used to recover the su gar chain from reaction mixtures. The high-affinity interaction of the biotinyl group with multivalent avidin or streptavidin can be used to create the functional equivalent of neoglycoproteins carrying multipl e copies of oligosaccharides of defined structure. These complexes all ow the production of IgG antibodies directed against the oligosacchari de chain. They can also harness the power of (strept)avidin-biotin tec hnology for the detection and isolation of oligosaccharide-specific re ceptors from native sources of recombinant libraries.