Abstract
α-D-Mannosyl-maltotriose (Man-G3) were synthesized from methyl α-mannoside and maltotriose by the transfer action of α-mannosidase. (Man-G3)-βCD and (Man-G3)2-βCD were produced in about 20% and 4% yield, respectively when Aerobacter aerogenes pullulanase (160 units per 1 g of Man-G3) was incubated with the mixture of 1.6 M Man-G3 and 0.16 M βCD at 50°C for 4 days. The reaction products, (Man-G3)-βCD were separated to three peaks by HPLC analysis on a YMC-PACK A-323-3 column and (Man-G3)2-βCD were separated to several peaks by HPLC analysis on a Daisopak ODS column. The major product of (Man-G3)-βCDs was identified as 6-O-α-(63-O-α-D-mannosyl-maltotriosyl)-βCD by FAB-MS and NMR spectroscopies. The structures of (Man-G3)2-βCDs were analyzed by TOF-MS and NMR spectroscopies, and confirmed by comparison of elution profiles of their hydrolyzates by α-mannosidase and glucoamylase on a graphitized carbon column with those of the authentic di-glucosyl-βCDs. The structures of three main components of (Man-G3)2-βCDs were identified as 61,62-, 61,63- and 61,64-di-O-(63-O-α-D-mannosyl-maltotriosyl)-βCD.
