Immunohistochemical localization of β-amylase in resting barley seeds

The cellular localization of β-amylase (EC 3.2.1.2) in resting barley seeds was investigated by immunohistochemistry. The monospecificity of the antibodies used was shown by immunoelectrophoresis and western blotting. An adaptation of the immunofluorescence technique allowed the localization of β-amylase. free of autofluorescence, in the different parts of the seed. In endosperm, there was β-amylase protein in aleurone layers, only in the starchy endosperm, where the distribution of the enzyme was not uniform. The β-amylase of starchy endosperm. which can be in a free or a hound form, was mainly localized around starch granules of different sizes. In the embryo. β-amylase was present only in the part of the scutellum in front of the first leaf. By immunoquantitation after separation of the seed parts, its was shown that the ratio between the amounts of enzyme in embryo and endosperm was less than 1/3000.