REACTION-MECHANISM OF ISOMALTOOLIGOSACCHARIDES SYNTHESIS BY ALPHA-GLUCOSIDASE FROM ASPERGILLUS-CARBONARIOUS

An alpha-glucosidase from Aspergillus carbonarious CCRC 30414 was employed for investigating the enzymatic synthesis of isomalntooligosaccharides from maltose. The enzyme transferred a glucose unit from the nonreducing end of maltose and other alpha-linked glucosyl oligosaccharides to glucose and other glucosyl oligosaccharides which function as accepting co-substrates. The transfer of a glucose unit occurs most frequently to the 6-OH position of the nonreducing end of acceptor, but transfer to 4-OH position also occurs. Treatment of 30 % (w/v) maltose with the enzyme under optimum conditions afforded more than 50 % isomaltooligosaccharides.