Isolation, purification, and characterization of cyclomaltotetradecaose (ι-cyclodextrin), cyclomaltopentadecaose (κ- cyclodextrin), cyclomaltohexadecaose (λ-cyclodextrin), and cyclomaltoheptadecaose (μ-cyclodextrin)

Abstract

Although it has already been found that cyclodextrin glucanotransferase (CGTase) produces cyclodextrins (CDs) composed of six of thirteen glucopyranose units, the existence of CDs which have more than fourteen glucopyranose units has still not been confirmed. Cyclomaltotetradecaose (ι-CD), cyclomaltopentadecaose (κ-CD), cyclomaltohexadecaose (λ-CD) and cyclomaltoheptadecaose (μ-CD) are a new series of large-ring CDs composed of 14-17 α-(1→4)-linked D-glucopyranose units, respectively, ι-, κ-, λ- and μ-CD were purified from the commercially available CD powder produced by CGTase, by a combination of HPLC and column chromatography. The molecular weights of ι-, κ-, λ- and μ-CD were determined by FAB-MS, and their cyclic structures were identified by 1H-NMR and 13C-NMR. The 13C-NMR chemical shifts of ι-, κ-, λ- and μ-CD were elucidated and compared with those of δ-, ε-, ζ- , η- and θ-CD, and their structures were predicted from the results.