CHARACTERIZATION OF 5 ISOMERS OF BRANCHED CYCLOMALTOHEPTAOSE (BETA-CD) HAVING DEGREE OF POLYMERIZATION (D.P.) = 9 - REINVESTIGATION OF 3 POSITIONAL ISOMERS OF DIGLUCOSYL-BETA CD

It has been confirmed by methylation analyses and chemical syntheses that three isomers of branched cyclomaltoheptaose (beta-CD) isolated from the mother liquors of a large-scale preparation of beta-CD with Bacillus ohbensis cyclomaltodextrin glucanotransferase are 6(1),6(4)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (1), 6(1),6(3)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (2), and 6-O-(alpha-isomaltosyl)-cyclomaltoheptaose (4) instead of 6(1),6(2)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (3), which was erroneously characterized in an earlier paper 1. Compound 3 has been newly isolated from a glucosyl-beta-CD mixture prepared by hydrolysis with glucoamylase of a maltosyl-beta-CD mixture, synthesized from maltose and beta-CD through the reverse action of pullulanase. Chromatographic behavior and spectral data (C-13-n.m.r. and f.a.b.-m.s.) of these isomers of branched beta-CD (1-4), as well as those of another isomer prepared by the reverse action of hydrolytic enzymes, 6-O-(alpha-maltosyl)-cyclomaltoheptaose (5), were compared.