Heterobifunctional Reagents for Cross-Linking of Sugar with Protein

N-Bromoacetylsulfanilyl chloride and p-bromoacetamidobenzoyl chloride were synthesized as heterobifunctional reagents for the cross-linking of sugar with protein. These reagents react with the primary hydroxyl group of a sugar at the acid chloride group and with amino and imidazole groups of protein at the bromoacetyl group. Methyl α-D-glucoside, selected as a model sugar, reacts with these reagents to form methyl 6-O-(N-bromoacetylsulfanilyl)-α-D-glucoside and methyl 6-O-(p-bromoacetamidobenzoyl)-α-D-glucoside, respectively. These sugar derivatives combine with bovine serum albumin at weakly alkaline pHs. More than 10 of the sugar derivatives can be incorporated into one molecule of the albumin.