On the secretion of α-amylase by barley aleurone layers after incubation in gibberellic acid.

Gel filtration and centrifugation studies were used to study the distribution of α-amylase activity in homogenates of barley (Hordeum vulgare L.) aleurone layers. The results obtained were consistent with the hypothesis that α-amylase is secreted via membrane-bound vesicles. The α-amylase activity in an homogenate of barley aleurone layers was derived not only from the enzyme retained in the aleurone cells but also from enzyme previously secreted from the cells but apparently retained by the cell walls. The amount of α-amylase retained by the cell wall was influenced by factors such as the buffer in which the layers were incubated or the presence of Actinomycin D in the incubation medium.