Molecular species in the protein body II (PB-II) of developing rice endosperm.

The molecular weight and subunit composition ofglutelin, the major storage protein of rice, in the major type of protein bodies of developing rice seeds was examined by gradient and twodimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).Glutelin in the protein body was the assembled from heterogeneous subunits, and the molecular weights were estimated to be 64, 140, 240, 320, 380, and 500k by gradient SDS-PAGE.High molecular weight proteins (larger than 2,000 k) were also observed.The two-dimensional SDS-PAGE under reduced conditions showed, that the glutelin in the protein body was composed of two groups of polypeptides, 22~23 and 37~39k, bound by disulfide linkages.