Isolation and structural analyses of positional isomers of 61,6n-di-O-(N-acetyl-β-d-glucosaminyl)cyclomaltoheptaose (n=2, 3, and 4) and 6-O-[6-O-(N-acetyl-β-d-glucosaminyl)-N-acetyl-β-d-glucosaminyl]cyclomaltoheptaose Original Research Article

6-O-[6-O-(N-acetyl-β-d-glucosaminyl)-N-acetyl-β-d-glucosaminyl]cyclomaltoheptaose (βCD) and three positional isomers of 61,6n-di-O-(N-acetyl-β-d-glucosaminyl)cyclomaltoheptaose (n=2, 3, and 4) in a mixture of products from βCD and N-acetylglucosamine by the reversed reaction of β-N-acetylhexosaminidase from jack bean were isolated and purified by HPLC. The structures of four isomers of di-N-acetylglucosaminyl-βCDs were determined by FABMS and NMR spectroscopy. The degree of polymerization of the branched oligosaccharides produced by enzymatic degradation with bacterial saccharifying α-amylase (BSA) was established by LC–MS methods.