N-Terminal Sequence of Amino Acids and Some Properties of an Acid-stable α-Amylase from Citric Acid-Koji (Aspergillus usamii var.)

Abstract

An acid-stable α-amylase (AA) was purified from an acidic extract of citric acid-koji (A. usamii var.). The N-terminal sequence of the first 20 amino acids of the enzyme was identical with that of AA from A. niger, but the two enzymes differed in molecular weight. HPLC analysis for identifying the anomers of products indicated that the AA hydrolyzed maltopentaose (G5) at the third glycoside bond predominantly, which differed from Taka-amylase A and the neutral α-amylase (NA) from the citric acid-koji.