Release of N-glycans by Enzymatic Methods

Abstract

To release oligosaccharide moiety from the original glycoprotein molecule, there are two widely used methods: the typical chemical method, hydrazinolysis; and the enzymatic method using glycoamidase A (from almond) or N-glycanase F (from Flabobacterium meningosepticum). In the past, endo-β-N-acetylglucosaminidase used to be applied, too, but the disadavantage of this enzyme is that it always leaves one of the two reducing ends N-acetylglucosamine molecules of the oligosaccharide moiety on the substrate protein molecules. On the contrary, glycoamidase A or N-glycanase F releases the whole sugar moiety completely from the substrate protein portion. Therefore, the application of the latter is the most convenient method for structural study of oligosaccharide moieties in various glycoproteins.