Synthesis of Novel Heterobranched β-Cyclodextrins Having β-D-N-Acetylglucosaminyl-Maltotriose on the Side Chain

Abstract

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 (Glc₃) and Gal-GlcNAc-Glc₃ were produced with hydrolysis of GlcNAc-βCD by cyclodextrin glycosyltransferase, and Gal-GlcNAc-βCD by bacterial saccharifying α-amylase respectively. Finally, GlcNAc-Glc₃-βCD and Gal-GlcNAc-Glc₃-βCD were synthesized in 5.2% and 3.5% yield when Klebsiella pneumoniae pullulanase was incubated with the mixture of GlcNAc-Glc₃ and βCD, or Gal-GlcNAc-Glc₃ and βCD respectively. The structures of GlcNAc-Glc₃-βCD and Gal-GlcNAc-Glc₃-βCD were analyzed by FAB-MS and NMR spectroscopy and identified as 6-O-α-(6³-O-β-D-N-acetylglucosaminyl-maltotriosyl)-βCD, and 6-O-α-(4-O-β-D-galactopyranosyl-6³-O-β-D-N-acetylglucosaminyl-maltotriosyl)-βCD respectively.