Transglucosylation activities of multiple forms of α-glucosidase from spinach

Transglucosylation activities of spinach α-glucosidase I and IV, which have different substrate specificity for hydrolyzing activity, were investigated. In a maltose mixture, α-glucosidase I, which has high activity toward not only maltooligosaccharides but also soluble starch and can hydrolyze isomaltose, produced maltotriose, isomaltose, and panose, and α-glucosidase IV, which has high activity toward maltooligosaccharides but faint activity toward soluble starch and isomaltose, produced maltotriose, kojibiose, and 2,4-di-α-D-glucosyl-glucose. Transglucosylation to sucrose by α-glucosidase I and IV resulted in the production of theanderose and erlose, respectively, showing that spinach α-glucosidase I and IV are useful to synthesize the α-1,6-glucosylated and α-1,2- and 1,4-glucosylated products, respectively.