Abstract
We have established some novel synthetic transformations of simple sugars into useful oligosaccharides utilizing the transglycosylation of glycosidases in aqueous -organic solvent system. p-Nitrophenyl penta-N-acetyl-β-chitopentaoside, which is useful as a novel substrate for lysozyme assay, was efficiently synthesized through a lysozyme-catalyzed transglycosylation on penta-N-acetylchitopentaose and p-nitrophenyl β-N-acetylglucosaminide. In this case, the use of an aqueous-DMSO system in the reaction not only ensured the solubility of chromogenic substrate, but also resulted in the high yield of the desired compound. This concept was introduced for the preparation of p-nitrophenyl α-maltopentaoside from maltopentaose and p-nitrophenyl α-Dglucoside by the use of maltotetraose-forming amylase from Pseudomonas stutzeri. Furthermore, p-nitrophenyl N-acetyl-Iactosaminide and p-nitrophenyl N-acetyl -allolactosaminide were regioselectively synthesized from lactose and p-nitrophenyl N acetylglucosaminide by using the transglycosylation of β-D-galactosidase from Bacillus circulars by controlling the concentration of acetonitrile in the reaction system, respectively.
