| Research Abstract |
1.Preparation and Characterization of 6^1,6^2-,6^1,6^3-, and 6^1,6^4-Di-O-(α-L-fucopyranosyl)-β- cyclodextrins and Study of Their Functions
Three positional isomers of 6^1,6^n-di-O-(α-L-fucopyranosyl)-βCDs [6^1,6^n-di-O- (α-L-Fuc)-βCDs, n=2-4] were chemically synthesized by using the authentic compounds, 6^1,6^n-di-O-(tert-butyldimethylsilyl)-βCDs (n=2-4) as the fucosyl intermediates, and the fucosyl donor, 2,3,4-tri-O-acetyl-L-fucopyranosyl trichloroacetimidate. Their structures were analyzed by HPLC, MS, and NMR spectroscopy. The specific interaction between those compounds and fucose-binding lectin AAL (Aleuria aurantia lectin) were investigated by using an optical biosensor. The binding affinity was 6^1,6^4- > 6^1,6^3- > 6^1,6^2-di-O-(α-L-Fuc)-βCD > 6-O-(α-L- Fuc)-βCD in the comparison by the fucose-binding position.
2.Synthesis of Novel Heterobranched β-Cyclodextrins Having β-D-N-Acetylglucosaminyl-Maltotriose on the Side Chain
GlcNAc-βCD, N-acetylglucosaminyl-β-cyclodextrin ; Gal-Gl
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cNAc-βCD, galactosyl-N-acetyl-glucosaminyl-βCD ; GlcNAc-Glc_3-βCD, N-acetylglucosaminyl-maltotriosyl-βCD ; Gal-GlcNAc-Glc_3-βCD, galactosyl-Nacetylglucosaminyl-maltotriosyl-βCD. From a mixture of N-acetylglucosaminyl-β-cyclodextrin (GlcNAc-βCD) and lactose, β-D-galactosyl-GlcNAc-βCD (Gal-GlcNAc-βCD) was synthesized by the transfer action of β-galactosidase. GlcNAc-maltotriose (Glc_3) and Gal-GlcNAc-Glc_3 were produced with hydrolysis of GlcNAc-βCD by cyclodextrin glycosyltransferase, and Gal-GlcNAc-βCD by bacterial saccharifying α-amylase respectively. Finally, GlcNAc-Glc_3-βCD and Gal-GlcNAc-Glc_3-βCD were synthesized in 5.2% and 3.5% yield when Klebsiella pneumoniae pullulanase was incubated with the mixture of GlcNAc-Glcs and βCD, or Gal-GlcNAc-Glc_3 and βCD respectively. The structures of GlcNAc-Glc_3-βCD and Gal-GlcNAc-Glc_3-βCD were analyzed by FAB-MS and NMR spectroscopy and identified as 6-O-α-(6^3-O-β-D-N-acetylglucosaminyl-malto- triosyl)- βCD, and 6-O-α-(4-O-β-D-galactopyranosyl-6^3-O-β-D-N-acetylglucosaminyl-maltotriosyl)-βCD respectively. Less
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