Enzymatic synthesis of a beta-D-galactopyranosyl cyclic tetrasaccharide by beta-galactosidases

Carbohydr Res. 2004 Jun 22;339(9):1603-8. doi: 10.1016/j.carres.2004.04.005.

Abstract

The galactosyl transfer reaction to cyclo-[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->] (CTS) was examined using lactose as a donor and beta-galactosidases from Aspergillus oryzae and Bacillus circulans. The A. oryzae beta-galactosidase produced three galactosyl derivatives of CTS. The main galactosyl derivative produced by the A. oryzae enzyme was identified as 6-O-beta-D-galactopyranosyl-CTS, cyclo-[-->6)-alpha-D-Glcp-(1-->3)-[beta-D-Galp-(1-->6)]-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->]. The B. circulans beta-galactosidase also synthesized three galactosyl-transfer products to CTS. The structure of main transgalactosylation product was 3-O-beta-D-galactopyranosyl-CTS, cyclo-[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-[beta-D-Galp-(1-->3)]-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->]. These results showed that beta-galactosidase transferred galactose directly to the ring glucose residue of CTS.

MeSH terms

  • Aspergillus oryzae / enzymology
  • Bacillus / enzymology
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Carbon Isotopes
  • Chromatography, High Pressure Liquid
  • Galactose / analogs & derivatives*
  • Galactose / chemical synthesis*
  • Galactose / chemistry
  • Lactose / chemistry
  • Mass Spectrometry
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Substrate Specificity
  • beta-Galactosidase / chemistry
  • beta-Galactosidase / genetics
  • beta-Galactosidase / metabolism*

Substances

  • Carbon Isotopes
  • beta-Galactosidase
  • Lactose
  • Galactose