α-Amylase changes during development and germination of maize kernels

Abstract

Summary α-Amylase activity appeared early during the development of maize kernels, culminated and then decreased to a low level at maturity. The activity increased again during germination to levels much higher than those detected during kernel development. As observed for other cereals, all isoforms of the enzyme identified in developing kernels were also present in germinating kernels. Three distinct antigens were detected in germinating kernels with antiserum against the maize α-amylase. Most of the α-amylase activity of developing maize kernels was equally distributed between the embryo and endosperm, although the bulk of the enzyme is located in the pericarp of other developing cereal seeds. In the germinating kernels the scutellum appeared to produce and secrete as much α-amylase as the aleurone layer; the secretory process in both tissues was Ca2+ independent. Clear-cut differences are thus displayed between the α-amylases of maize seeds and those of the well characterized enzymes of wheat, barley and rice seeds.