Purification and properties of alpha-amylase from Aspergillus oryzae ATCC 76080.
An alpha-amylase was purified from the solid cultural extract of Aspergillus oryzae ATCC 76080 by sequential steps of amylopectin affinity adsorption, DEAE-Sepharose ion-exchange chromatography and Sephacryl S-200 HR gel filtration. By these steps, the purity of the enzyme increased by 16 fold and recovery of the enzyme activity was 45%. The purified 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 30 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. Mercuric ion (0.3 mM), DNFB# (6 mM), NBSI (6 mM) and NAI (6 mM) inhibited the activity of the enzyme. The main products for hydrolysis of maltoheptaose by the enzyme were maltotriose and maltotetraose.
Chang
C T
CT
Department of Food and Nutrition, Providence University, Shalu, Taiwan, R.O.C.
Tang
M S
MS
Lin
C F
CF
D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D013696:Temperature; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D009844:Oligosaccharides; D013213:Starch; D000516:alpha-Amylases