Cereal Chem. 70:101-104   |  VIEW ARTICLE

Characterization of Poorly Digested Protein of Cooked Rice Protein Bodies.

A. P. Resurreccion, X. Li, T. W. Okita, and B. O. Juliano. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Poorly digested protein bodies from cooked IR58 milled rice were prepared by destarching with Aspergillus oryzae alpha-amylase followed by one or two pepsin treatments. The preparation was further purified by gel filtration through a Bio-Gel A-5m column with 0.5% sodium dodecyl sulfate in 0.05M Tris-HCl (pH 8.6) buffer as eluant. The major polypeptide had a high sulfur amino acid content and a molecular size of about 13 kDa, slightly smaller than that of the 15-kDa rice prolamin. The 13-kDa polypeptide was identified as a prolamin based on Western blot analysis, and it is probably a proteolytic product of the class of 15-kDa rice prolamins that are rich in sulfur-containing amino acids.