Biotinylated Aminopyridine

Fluorescence of the diaminopyridine group allows detection of conjugates down to the pico-mole range, with excitation and emission maxima at 345 and 400 nm, respectively. For detection of BAP and its conjugates, the optimal buffer environment is less than pH 5, because its fluorescent properties are pH dependent. A preferred buffer is sodium acetate at pH 4. 

The conjugation of BAP to oligosaccharides can be done by the following protocol based on the method of Toomre and Varki (1994). 

Dissolve an oligosaccharide or glycan having a reducing end to be modified in 2 1 pyri-dine/glacial acetic acid (vol/vol) with a total reaction volume of 10-100 pi. If the carbohydrate initially is insoluble in the reaction solution, a prior dissolution in a minimal amount of DMSO or water can be done and then an aliquot transferred to the reaction medium. 

Add to the solution a 50-fold molar excess of BAP over the estimated amount of carbohydrate present in the reaction mixture. 

Heat at 80°C in a sealed Reactivial (Thermo Fisher) for 1 hour. 

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