A Simple Method to Differentiate between α- and β-Amylase

Physical and chemical properties often have been used to differentiate a-amylase from /3-amylase (2-4, 7). a-Amylase is insensitive to high temperatures and heavy metal ions, requires Ca2+ for activity, and is inactivated at a low pH. /8-Amylase is sensitive to high temperatures and heavy metal ions, does not require Ca2+, and is stable at a low pH. Enzymatic differences between the two forms of amylase have been used to a lesser extent. One enzymatic characteristic that has been used is the dissimilarity of the end products of amylolytic hydrolysis (3, 7). /3-Amylase hydrolyzes soluble starch or amylose, yielding only maltose as an end product. Hydrolysis of soluble starch or amylose by a-amylase occurs randomly, releasing a large amount of oligosaccharides or dextrin. The dextrin is then hydrolyzed, yielding a large quantity of maltose and little glucose and maltotriose (1). At this point, hydrolysis by aor 3-amylase would yield essentially similar end products. If the further hydrolysis of maltose by a-amylase is rate-limiting and is dependent upon the concentration of the enzyme and pH (7), little or no glucose would be expected. As a result, the chromatographic display of the end products would be similar to that obtained from /3-amylase hydrolysis.