Cereal Chem 72:269-274  |  VIEW ARTICLE

In Situ Location of a Starch Granule Protein in Durum Wheat Endosperm by Immunocytochemistry.

P. Rayas-Duarte, S. F. Robinson, and T. Freeman. Copyright 1995 by the American Association of Cereal Chemists, Inc. 

Starch granule protein (SGP) was extracted with 0.1N NaCl from starch isolated from durum wheat Triticum turgidum cv. Vic flour (53% extraction). Ultrafiltered and lyophilized SGP was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A 32-kDa SGP was identified, excised from the gel, and used as an antigen to produce polyclonal antibodies. Western blotting confirmed antibody production. The antibodies were used in a gold label transmission electron study of wheat endosperm tissue seven days after anthesis. Significance was determined using stereological techniques and nonparametric one-way analysis of variance. The number of gold particles per square micrometer area for starch (8.92), cell wall (0.53), and cytoplasm (0.04) differed significantly (P less than 0.01). Labeling occurred throughout the starch, indicating that the 32-kDa starch granule protein is inherent to starch and is not localized on the granule surface.