1-Deoxynojirimycin
(1) is a potent inhibitor of mammalian and rice a-glucosidase. Several glucosides of 1 were synthesized by use of the native and immobilized enzyme and their effect on various enzymes was investigated. Transglucosylation reactions using rice cY-glucosidase, yeast LY-and p-glucosidases purified from Rhodotoda lactosa were performed with maltose or cellobiose as a glucose donor and N_(benzyloxycarbonyl)-l-deoxynojirimycin ( 2) as an acceptor. The transglucosylation reaction using native rice cu-glucosidase afforded 3-0~-o-glucopyranosyl-N-(benzyloxycarbonyl)-l-deoxynojirimycin (4), 4-0-(Y-o-glucopyTanosyl-N-(ben~loxycarbonyl)_l-deoxynojirimycin (5), and 2-O-cy-o-glucopyranosyl-N-(benzyloxycarbonyl)-l-deoxynojirimycin
(3) in yields of 40, 13, and 2%, respectively, after 30 min. The transglucosylation reaction using immobilized rice cu-glucosidase was similar to that using the native enzyme. In the system using native yeast cy-glucosidase, 3, 5, and 4 were formed in yields of 34, 13, and 6%, respectively, after 15 h. The immobilization of yeast cw-glucosidase caused a significant decrease in transglucosylation activity. Yeast /3-glucosidase showed a high transglucosylation activity and incubation with the reaction system afforded 2-0_8-o-glucopyranosyl-N-(benzyloxycarbonyl)-l-deoxynojirimycin ( 6) and 4-O-~-~-glucopyranosyl-N-(benzyloxycarbonyl~l-deoxynojirimycin (7) in yields of 69 and 3%, respectively, after 3 h. The transglucosylation reaction using immobilized yeast /3-glucosidase preferentially afforded 6 in a yield of 73% after 3 h. After removal of N-benzyloxycarbonyl group from the product glucosides, their glycosidase inhibitory activities were measured. 3-O-cx-o-Glucopyranosyl-l-deoxynojirimycin (9) retained the potent inhibition of 1 against rat intestinal sucrase activity and was more effective than 1 against * Corresponding author.