Cereal Chem 55:809 - 817.  |  VIEW ARTICLE
Electrophoretic and Immunochemical Properties of the 12S Rapeseed Protein.

T. A. Gill and M. A. Tung. Copyright 1978 by the American Association of Cereal Chemists, Inc. 

The 12S rapeseed protein as prepared by gel filtration of an alkaline extract of commercial meal was subjected to polyacrylamide disc gel electrophoresis and immunoelectrophoresis, both by conventional means and in the presence of sodium dodecyl sulfate (SDS). The 12S isolate was separated into a major component and a slower moving minor component by disc gel electrophoresis, while SDS gel electrophoresis resulted in the separation of subunits with apparent molecular weights of approximately 42,000, 37,600, 30,100, 17,400, and 12,200 daltons. Electrophoretic patterns of nonreduced and reduced samples indicated the presence of intermolecular disulfide bonds, although the cystine content was low. The isolate contained a high molecular weight component, but immunoelectrophoretic analysis resulted in the formation of one homogeneous pair of precipitin arcs. This would suggest that the 12S protein self- associates to form aggregates of higher molecular weight (dimers). Schiff staining of SDS gels indicated that the fragment with the lowest molecular weight contained most of the carbohydrate. This fragment was immunoresponsive in the presence of SDS, whereas the other subunits were not. One explanation for this phenomenon could be that the low molecular weight glycopeptide is located on the surface of the aggregate.