Galactosylation of Branched Cyclodextrins by β-Galactosidases

Transgalactosylated derivatives of branched cyclodextrins (CDs) were synthesized with Bacillus circulars β-galactosidase under the co-existence of lactose and branched CDs. The structure of the transfer products were determined by β-galactosidase digestion, FAB-MS, and 13C-NMR analysis. B. circulans β-galactosidase produced B-galactosyl-(1→4)-α-glucosyl-(1→6)-βCD and β-galactosyl-(1→4)-β-galactosyl-(1→4)-α-glucosyl-(1→6)-1SCD, or β-galactosyl-(1→4)-α-glucosyl-(1→4)-α-glucosyl-(1→6)-CD and β-galactosyl-(1→4)-β-galactosyl-(1→4)-α-glucosyl-(1→4)-α-glucosyl-(1→6)-αCD from the mixture of lactose and glucosyl-BCD or maltosyl-αCD, respectively. Aspergillus oryzae and Penicillium multicolor β-galactosidases also produced transgalactosylated products of branched CDs. These structures are now under investigation.