Cereal Chem 56:402 - 406.  |  VIEW ARTICLE
Studies of Rice Proteins by Crossed Immunoelectrophoresis, Gel Electrophoresis, and Isoelectric Focusing.

A. I. Shadi and R. Djurtoft. Copyright 1979 by the American Association of Cereal Chemists, Inc. 

Soluble proteins (albumins and globulins) of two rice varieties were investigated by crossed immunoelectrophoresis. We could distinguish 28 or 29 individual components in a salt extract of the embryo and endosperm of the rice grain. The concentration of some proteins seemed to be higher in the embryo than in the endosperm; some were characteristic of only one variety. After seven days of germination in the dark, extracts of variety IR 1561-228 roots and shoots were subjected to immunoelectrophoretic study of proteins. Most proteins were identified in the embryo. All soluble proteins in the whole grain also were found in endosperm extracts. By specific staining methods, three phosphataes, one esterase, and one aminopeptidase were identified in the rice extract. By sodium dodecyl sulfatepolyacrylamide gel electrophoresis, the two rice varieties were shown to have two major subunits with molecular weights of 12,000 and 20,000 and relatively minor subunits with molecular weights of about 31,000, 56,000, and 90,000. After germination, the 20,000 mol wt band nearly disappeared from the extractions of roots, shoots, embryo, and endosperm. The soluble rice proteins were studied further by isoelectric focusing. Twenty-one protein bands with different pI from 4.0 to 8.0 were found, among which were the three phosphatases.