Characterization of the α-Amylases Synthesized by Aleurone Layers of Himalaya Barley in Response to Gibberellic Acid

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Abstract
The GA3-induced .alpha.-amylases from the aleurone layers of Himalaya barley (H. vulgare L. cv Himalaya) were purified by cycloheptaamylose-Sepharose affinity chromatography and fractionated by DEAE-cellulose chromatography. Four fractions (.alpha.-amylases 1-4) were obtained which fell into 2 groups (A and B) on the basis of a number of characteristics. Major differences in serological characteristics and in proteolytic fingerprints were found between group A (.alpha.-amylases 1 and 2) and group B (.alpha.-amylases 3 and 4). The lag time for appearance of group B enzyme activity was longer than for group A and the appearance of group B required higher GA3 levels than group A. The components of each group behaved similarly, although differences in proteolytic fingerprints were detected. Apparently, GA3 differentially controls the expression of 2 .alpha.-amylase genes or groups of genes giving rise to 2 groups of .alpha.-amylases with many different properties.