Saccharide or Glycan Groups

The modification of molecules with saccharides also has the effect of increasing the hydrophilicity of the resultant complex due to the presence of multiple hydroxyl groups. Native glycan modification of proteins functions in much the same manner, because the carbohydrate 

Lactose modified molecule via amide bond linkage 

Some reports even indicate that the conjugation of proteins or peptides with carbohydrates can increase dramatically their activity compared to that of the native state (Susaki et al., 1998). Carbohydrates also can provide a protective effect on modified peptides toward proteolytic digestion (Rudd et al., 1994) or mask recognition of a peptide by the immune system (Harding et al., 1993). The creation of neoglycoproteins thus can affect the activity of peptides and proteins, which are not normally glycosylated in vivo. 

The following sections describe several examples of saccharide modification for the purpose of bioconjugation, the study of glycan function, to prepare immunogens, or to increase the water solubility of a modified molecule. 

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