Isolation by HPLC of the positional isomers of 61,2n-di-O-α-d-galactopyranosylcyclomaltohexaose (n = 1–6) and determination of their structures by enzymatic degradation

The six positional isomers of 61,2n-di-O-α-d-galactopyranosylcyclomaltohexaose (α-cyclodextrin, αCD, n = 1–6), which were produced from αCD and melibiose by transgalactosylation with coffee bean α-galactosidase, were isolated by HPLC on a reversed-phase column and a graphitized carbon column. The structures of those isomers were elucidated by LC-MS analyses of enzymatic degradation products with cyclomaltodextrin glucanotransferase and α-galactosidase.