ISOLATION AND STRUCTURAL-ANALYSES OF POSITIONAL ISOMERS OF 6(M)-DI-O-ALPHA-D-MANNOPYRANOSYL-CYCLOMALTOOCTAOSE (M = 2-5) AND N-O-ALPHA-D-MANNOPYRANOSYL)-ALPHA-D-MANNOPYRANOSYL CYCLOMALTOOCTAOSE (N = 2, 3, 4, AND 6)

Eight positional isomers of 6(m)-di-O-alpha-D-mannopyranosyl-cyclomalt ooctaose (gamma CD) (m = 2-5) and n-O-alpha-D-mannopyranosyl)-D-mannop yranosyl-gamma CD (n=2, 3, 4, and 6) in a mixture of products from gam ma CD and D-mannose by condensation reaction of alpha-mannosidase from jack bean were isolated by HPLC. The structures of four isomers of n- O-alpha-D-mannopyranosyl)-D-mannopyranosyl-gamma CD were elucidated by NMR spectroscopy. On the other hand, four positional isomers of 6(1), 6(m)-di-O-alpha-D-mannopyranosyl-gamma CD were determined by LC-MS ana lysis of degree of polymerization of the branched oligosaccharides pro duced by enzymatic degradation with bacterial saccharifying alpha-amyl ase (BSA), and combination of BSA and glucoamylase. Similarly cyclomal todextrin glucanotransferase also digested these isomers. (C) 1998 Els evier Science Ltd. All rights reserved.