Abstract
This article describes the design, synthesis and properties of novel β-glycosidase inhibitors, β-glycosylamidines, aiming at developing easily accessible glycosidase inhibitors that could be used as an affinity ligand. β-Glycosylamidines, in which glycopyranose is connected via a β-N-glycoside linkage with a substituted amidine, are easily accessible, but highly potent β-glycosidase inhibitors. The inhibition is selective with respect to the enzyme's glyconand stereospecificities, and a series of β-glycosylamidines of different glycon types is synthesized in quantities from the corresponding sugar in two steps. The positively charged amidine bound tightly with the enzyme active site by charge interaction with an anionic form of the catalytic acid/base carboxy group. The properties of β-glycosylamidines have been used successfully as an affinity ligand for the purification of β-glycosidases from natural samples according to the glycon substrate specificity. Despite high affinity with the ligand, the adsorbed enzyme was eluted readily by adding sugar or by lowering the pH below the pKa of the catalytic acid/base carboxy of the enzyme. The latter method is applicable to the affinity purification of a wide variety of β-glycosidases by controlling the adsorption and desorption properties by changing the pH.
