PURIFICATION AND PROPERTIES OF ALPHA-AMYLASE FROM ASPERGILLUS-ORYZAE ATCC-76080

An alpha-amylase was purified from the solid cultural extract of Asper gillus oryzae ATCC 76080 by sequential steps of amylopectin affinity a dsorption, DEAE-Sepharose ion-exchange chromatography and Sephacryl S- 200 HR gel filtration. By these steps, the purity of the enzyme increa sed by 16 fold and recovery of the enzyme activity was 45%. The purifi ed enzyme had an optimal pH between 4 to 5, optimal temperature at 50 degrees C and a Km value of 0.22% for hydrolysis of starch. About 80% of the enzyme activity was lost after incubation at 50 degrees C for 3 0 min. The heat denaturation constant at 50 degrees C was 0.024 min(-1 ). The molecular weight was 52 kDa as determined by gel filtration. Me rcuric ion (0.3 mM), DNFB# (6 mM), NBSI (6 mM) and NAI (6 mM) inhibite d the activity of the enzyme. The main products for hydrolysis of malt oheptaose by the enzyme were maltotriose and maltotetraose.