ABSTRACT
The biochemistry of alpha-amylase in germinating cereal seeds has had a relatively history. Studies on alpha-amylase have been made in close relation to the brewery industry. Due to the development of recombinant DNA techniques, the mechanism of gibberellic acid-dependent inducible formation of alpha-amylase in barley seeds is receiving the vigorous attention of many investigators at the molecular level of gene expression. In some cereals such as barley, it appears quite evident that in the later stages of germination, endosperm starch is broken down by alpha-amylase produced and secreted from the surrounding aleurone layers. Rice seed alpha-amylase has been shown to be a typical secretory glycoprotein, and experimental results with the enzyme have increased our knowledge concerning the pathway and mechanism of secretory glycoprotein synthesis in higher plants. Among the numerous secretory proteins there are several non-glycoprotein-type single proteins such as serum albumin, insulin, and growth hormone, but the majority belong to the class of carbohydrate-bearing Asn-N-inked glycoproteins.
