Cereal Chem 62:11-18   |  VIEW ARTICLE
A Comparison of the Catalysis of Starch Components by Isoenzymes from the Two Major Groups of Germinated Wheat Alpha-Amylase.

J. E. Kruger and B. A. Marchylo. Copyright 1985 by the American Association of Cereal Chemists, Inc. 

Alpha-Amylase isoenzymes from the two major groups (GI and GIII) in germinated wheat were separated and purified by a two-step process consisting of affinity chromatography and chromatofocusing. The two groups, at equivalent enzymic activities, were compared for their ability to hydrolyze a variety of starch substrates. No significant differences were found in the catalytic hydrolysis of beta-limit dextrin, amylopectin, or amylose, as indicated by product distributions evaluated by high performance aqueous gel permeation chromatography. At 37 C, only the GIII group adsorbed onto large and small granules. Both groups solubilized starch; small granules were degraded faster than large granules. At 2 C, the adsorption characteristics only starch granules were identical for both groups. The GI and GIII isoenzymes had identical effects in lowering the amylograph viscosity of a wheat flour and in increasing its gassing power, which suggests that the action pattern of the two groups must be very similar.