Cereal Chem. 70:534-538   |  VIEW ARTICLE

Reaction Patterns of Maize alpha-Amylases with Soluble Starch, Granular Starch, and Maltooligosaccharides.

C. A. Knutson. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Action patterns of maize alpha-amylases on soluble starch, granular starch, and maltooligosaccharide substrates were evaluated. Enzyme fractions with low, intermediate, and high isoelectric points (pI) had specific patterns on soluble starch. Primary reactions on starch molecules and large oligosaccharides produced large quantities of oligosaccharides with degree of polymerization (DP)7 and smaller quantities of oligosaccharides with DP8-15. Secondary reactions, identified by the point at which net consumption of DP7 began to occur, consisted of the hydrolysis of oligosaccharides with DP7 and higher to fragments of DP6 and below. Each enzyme type showed characteristic primary and secondary patterns. For high-pI and low-pI enzyme forms, secondary action patterns were equivalent to patterns obtained by hydrolysis of DP7 maltooligosaccharide. For the intermediate-pI enzymes, the reaction with DP7 was complicated by transglycosylation, resulting in the formation of higher oligosaccharides from DP4 oligomers. For all forms, reactions on starch granules differed significantly from both the primary and secondary reactions on soluble starch.