An expression plasmid containing the agdA gene encoding Aspergillus oryzae ZL-1 α-glucosidase was constructed and expressed in Pichia pastoris X-33. The molar mass of the purified protein was estimated by SDS-PAGE. HPLC analysis showed that the purified enzyme has a transglucosylating activity with maltose as substrate. The main component of the enzyme products was panose, while amounts of isomaltose and isomaltotriose were very low or absent. pH 5.2 and temperature of 37 °C were optimum for enzyme activity.
