Enzymic Mechanism of Starch Breakdown in Germinating Rice Seeds: 8. Immunohistochemical Localization of beta-Amylase.

Rabbit antiserum against beta-amylase isolated from germinating seeds of rice was produced, and its specific cross-reactivity with beta-amylase was confirmed by means of Ouchterlony double immunodiffusion and immunoelectrophoresis procedures. The cellular localization of beta-amylase was studied by indirect fluorescence microscopy of thin sectioned germinating rice seed specimens (1-day stage) which had been fixed and treated with purified rabbit anti-beta-amylase immunoglobulin G followed by conjugation with fluorescein isothiocyanate-labeled goat antirabbit immunoglobulin G. It has been demonstrated that beta-amylase is uniformly associated with the periphery of starch granules in the starchy endosperm cells. The finding is discussed in relation to the general notion concerning the presence of the latent form of beta-amylase bound to protein bodies in cereal seeds.