Multiple forms of amylase induced by gibberellic acid in isolated barley aleurone layers

The addition of gibberellic acid to isolated aleurone layers of barley (Hordeum vulgare L.) causes the production and secretion of four alpha-amylases. Two of these are stable at pH 3.7 and are not inactivated by ethylenediaminetetraacetate. The other two represent the classical barley alpha-amylases; i.e., they are inactivated at pH 3.7 and by reagents which from complexes with divalent metal ions. All four forms are synthesized de novo in response to the addition of gibberellic acid.