Abstract
Biochemical studies of enzymatic reactions using their inhibitors (substrate analogues) are useful for understanding the catalytic mechanisms of enzymes, especially those which are difficult to explain only by biogenetic investigations. We have presented the rational molecular design of the carbohydrate active enzyme inhibitors on the basis of Phillips’s lysozyme-subsite model. 1) α-Amylase inhibitors: We performed a chemo-enzymatic transformation of maltooligosaccharides into both-end-modified oligono-lactones to be of potential utility as substrate analogue inhibitors for mammalian α-amylase. The products were L4G2O, L4G3O and BG3O, which are competitive inhibitors for mammalian α-amylase. In this case, the lactone form was essential for the occurrence of an α-amylase inhibitor. Administration of L4G2O produces significant improvements in both blood glucose and insulin response, and this evidence will provide the support for its therapeutic potential in treating diabetes mellitus and obesity. 2) β-Glycosidase inhibitors: cycloalkyl β-D-glucopyranosides were synthesized by the transglucosylation of a β-glucosidase from fungi. Among three β-glucopyranosides synthesized, only CPEM-β-G was found to inhibit the sweet almond enzyme activity. As it is easily expected that CPEM-β-G is much more likely to inhibit the activity of an enzyme from plant origin compared with that from fungi, we studied the possibility of using CPEM-β-G as an inhibitor of the β-glucosidase activities of extracts from cut flowers on the basis of their kinetic data. Finally, we have presented an outline of our experiments for the investigation of some β-glycosylamidines (highly selective inhibitors of β-glycosidases) as the results of our joint research.
