Synthesis of methyl 6-O-beta-inulotriosyl-alpha-D-glucopyranoside by intermolecular transglycosylation reaction of cycloinulo-oligosaccharide fructanotransferase

Combinatorial evaluation of the chiral discrimination of permethylated carbohydrates using fast-atom bombardment mass spectrometry

The chiral discrimination abilities of several variously permethylated carbohydrates toward various amino acid 2-propyl esters were combinatorially evaluated from the relative peak intensity of the 1:1 diastereomeric complex ions with the deuterium-labeled L-amino acid 2-propyl ester protonated ion and with the unlabeled D-amino acid 2-propyl ester protonated ions in FAB mass spectrometry. The chiral discrimination abilities evaluated using FAB mass spectrometry approximately corresponded to the ratio of the association constants (K(R)/K(S)) toward each enantiomer in the solution. Therefore, this evaluation method is very useful for the screening of the chiral discrimination abilities of carbohydrates and their derivatives.

Effects of various saccharides on cycloinulo-oligosaccharide fructanotransferase reaction: production of beta-inulotriosyl-alpha-D-mannopyranoside and 1-O-beta-inulotriosyl-alpha-L-sorbopyranose

The effects of various saccharides on the reaction of cycloinulo-oligosaccharide fructanotransferase with cycloinu-lohexaose were examined. In addition to beta-D-fructofuranosides and methyl alpha-D-glucopyranoside, D-mannose and L-sorbose were found to be effective acceptors in the reactions, and they enhanced the hydrolytic activity as effectively as methyl alpha-D-glucopyranoside. Hetero-tetrasaccharides were isolated as the major transfer products from both reaction mixtures. The isolates were identified by NMR spectroscopy as beta-inulotriosyl-alpha-D-mannopyranoside and 1-O-beta-inulotriosyl-alpha-L-sorbopyranose. Methyl beta-D-glucopyranoside was slightly effective and methyl alpha-D-mannopyranoside was not effective at all as the acceptor, but these saccharides strongly enhanced the hydrolytic activity. D-Glucosamine inhibited the enzyme activity.