Hormonal regulation of α-amylase inhibitor synthesis in germinating barley

Abstract

The in vivo synthesis of α-amylase and of a bifunctional inhibitor of endogenous α-amylase and subtilisin was studied in embryoless barley half grains treated with abscisic (ABA) and gibberellic (GA3) acids. Fluorography of newly synthesized proteins and of immunoprecipitated α-amylase and its inhibitor separated by SDS-PAGE showed that GA3 induces the production of large amounts of α-amylase while the synthesis of other proteins, including the α-amylase inhibitor, is reduced. In contrast, synthesis and/or accumulation of the inhibitor is induced in embryoless half seeds incubated with ABA. These results identify the α-amylase inhibitor as an ABA-induced protein in barley aleurone layers and suggest that it functions as an active mediator of amylase activity during the development and germination of barley seeds. © 1984 Carlsberg Laboratory.