ISOLATION BY HPLC OF THE POSITIONAL ISOMERS OF HETEROGENEOUS DOUBLY BRANCHED CYCLOMALTOHEXAOSE HAVING ONE ALPHA-D-GALACTOSYL AND ONE ALPHA-D-GLUCOSYL SIDE-CHAIN AND DETERMINATION OF THEIR STRUCTURES BY ENZYMATIC DEGRADATION

Each of the six and five positional isomers of 2(n)- and yl-6(l)-O-alp ha-D-glucopyranosyl-cyclomaltohexaose (alpha-cyclodextrin, alpha CD; 2 (n): n = 1-6, 6(n): n = 2-6), which were produced from 6-O-alpha-D-glu copyranosyl-alpha CD and melibiose by transgalactosylation with coffee bean alpha-galactosidase, were isolated by high-performance liquid ch romatography (HPLC) on a reversed-phase column and a graphitized carbo n column. The structures of those isomers were elucidated by analyses of enzymatic degradation products with cyclomaltodextrin glucanotransf erase and glucoamylase. (C) 1996 Elsevier Science Ltd.