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Homology between rice glutelin and oat 12 S globulin

1985; Elsevier BV; Volume: 829; Issue: 1 Linguagem: Inglês

10.1016/0167-4838(85)90063-9

1878-1454

Laurian S. Robert, Constance Nozzolillo, Illimar Altosaar,

Proteins in Food Systems

The rice glutelin fraction consists of a heterogeneous array of polypeptides wherein two subunit groups (19–22 kDa and 30–36 kDa) predominate. In the absence of a reducing agent, these subunit groups were found to be associated by disulfide linkage into molecules occurring between 50 and 62 kDa. The larger subunit group (30–36 kDa) was shown to display both molecular mass and charge heterogeneity and to possess relatively acidic pI values. The smaller subunit group (19–22 kDa) exhibited less heterogeneity and more basic pI values. All these characteristics are typical of oat 12 S globulin. Antibodies raised against purified oat 12 S globulin hybridized strongly to both subunit groups of rice glutelin upon Western blot analysis. The antibody also detected the glutelin subunits within the rice globulin fraction, indicating that they are partially soluble in saline solution. The low salt-solubility of rice glutelin is apparently related to extensive protein aggregation, bringing about the need for strong solvents for complete solubilization. Hence, rice glutelin, like oat 12 S globulin, is in fact a legumin-like protein.