Synthesis of monomethyl derivatives of p-nitrophenyl alpha-D-gluco, galacto, and mannopyranosides and their hydrolytic properties against alpha-glycosidases

All possible monomethyl derivatives of p-nitrophenyl alpha-D-gluco, galacto , and mannopyranosides were synthesized. Hydrolytic activities of alpha-glu cosidase (rice), alpha-galactosidases (green coffee bean, Mortierella vinac ea, and Aspergillus niger), and alpha-mannosidases (almond and jack bean) a gainst them were elucidated. The 6-O-methyl galactopyranoside and mannopyra noside were hydrolyzed by the M. vinacea alpha-galactosidase and the almond and jack bean alpha-mannosidases, respectively, while these enzymes did no t act on the 2-, 3-, and 4-O-methyl derivatives. On the other hand, lice al pha-glucosidase and green coffee bean and A. niger alpha-galactosidases had no hydrolyzing activities at all against the respective four monomethylate d substrates.