Biotinyl-L-3- 2-naphthyl -alanine hydrazide

BNAH may be coupled to reducing sugars without reduction, since the linkage formed between a hydrazide and an aldehyde is much more stable than that with an amine. 

In some cases, the ability to modify glycans at the reducing end without reduction preserves the carbohydrate s native structure sufficiently to allow interactions with proteins that would otherwise not interact if the bond were reduced. Therefore, depending on the ultimate use of the biotinylated carbohydrate, using a hydrazide mediated conjugation process can have advantages over the use of amine-biotin compounds. 

Another advantage of the BNAH derivative is that the conjugation reaction with reducing sugars can be done in aqueous conditions and in an environment that permits carbohydrate and biotinylation reagent solubility. Modified carbohydrates may be stored for at least 1 year at —20°C in a solution of water/methanol (9 1 v/v) without degradation. 

Dissolve 100 nmol of the carbohydrate to be modified and 500 nmol of BNAH in 25 pi of methanol (20 mM BNAH solution). 

Evaporate the solution to dryness and re-dissolve in 25 pi of either an acidic solution of methanol/water/acetic acid (74 8 8, v/v) or in a neutral solution consisting of methanol/ water (9 1, v/v), depending on the relative solubility of the carbohydrate. 

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