Addition of maltodextrins to the nonreducing-end of acarbose by reaction of acarbose with cyclomaltohexaose and cyclomaltodextrin glucanyltransferase Original Research Article

New kinds of acarbose analogues were synthesized by the reaction of acarbose with cyclomaltohexaose and cyclomaltodextrin glucanyltransferase (CGTase). Three major CGTase coupling products were separated and purified by Bio-Gel P2 gel-permeation chromatography. Digestion of the three products by beta-amylase and glucoamylase showed that they were composed of maltohexaose (G6), maltododecaose (G12), and maltooctadecaose (G18), respectively, attached to the nonreducing-end of acarbose. 13C NMR of the glucoamylase product (d-glucopyranosyl-acarbose) showed that the d-glucose moiety was attached α- to the C-4-OH group of the nonreducing-end cyclohexene ring of acarbose, indicating that the maltodextrins were attached α-(1→4) to the nonreducing-end cyclohexene of acarbose.