The role of ligand density in the enzymatic glycosylation of carbohydrates presented on self-assembled monolayers of alkanethiolates on gold

The biological activity of immobilized carbohydrates can show a dramatic dependence on the density of carbohydrate. This is the result of investigations with self-assembled monolayers that present N- acetylglucosamine groups as a model substrate for glycosylation by bovine β- 1,4-galactosyltransferase (GalTase; see picture). Surface plasmon resonance spectroscopy and carbohydrate-binding lectins were used to characterize the reaction at the interface. UDP-Gal = uridine diphosphogalactose.