Abstract
Chitooligosaccharide and maltooligosaccharide were initially converted into useful oligosaccha rides, utilizing glycosidase-mediated transglycosylation. Hexa-N-acetylchitohexaose as a biologically active substance and p-nitrophenyl penta-N-acetyl β-chitopentaoside as a novel substrate of lysozyme assay were synthesized from chitooligosaccharides by hen egg-white lysozyme. p- Nitrophenyl α-maltopentaoside was synthesized from maltopentaose by maltotetraose-forming amylase. It was further converted into end-blocked p-nitropheny 45-O-β-D-galactosyl-amaltopentaoside, which was designed as a substrate for diagnosis of human amylase in serum. Galactosylmaltooligonolactone was also designed and synthesized as substrate analogue inhibitor for mammalian α-amylase. Next an efficient method for synthesizing important di-, tri-, and tetrasaccharide units involved in glycoconjugate was developed. Beginning with β-galactosyl-disaccharide units library, a series of β-N-acetylglucosaminyl-, a-L-fucosyl- and β-mannnosyltrisaccharides were regioselectively synthesized by using some glycosidase-mediated transglycosylations. Consecutive synthesis of human milk tetrasaccharide and mucin type tisaccharide was carried out by enzymatic addition of two sugar residues. Such synthetic oligosaccharides were used to synthesize artificial glycopolymer. The polymers were shown to be useful as probes of carbohydrate recognition and modeling in the analysis of glycopolymer-lectin interaction.
