Isolation and Characterization of Two Types of Protein Bodies in the Rice Endosperm

TLDR: In this article, two types of proteinaceous particles were observed under the electron microscope in the starchy endosperm of rice seeds, one was spherical with lamellar structure (PB-I), while the other was stained homogeneously by osmium tetroxide and not lamlar structured (PBII).

Abstract: Two types of proteinaceous particles were observed under the electron microscope in the starchy endosperm of rice seeds. One was spherical with lamellar structure (PB-I), while the other was stained homogeneously by osmium tetroxide and not lamellar structured (PB-II). Both types of proteinaceous particles were effectively condensed from the homogenate of developing rice endosperm by an aqueous polymer two-phase system using dextran-DEAE dextran-polyethylene glycol. Separation of both types was carried out by sucrose density gradient centrifugation. These proteinaceous particles were recovered at specific gravities of 1.27 and 1.29 for PB-I and PB-II, respectively. The protein composition of these particles and their solubility fractionation were examined. Prolamin appeared in the PB-I fraction, whereas PB-II was rich in glutelin and globulin.