Cereal Chem. 70:452-457   |  VIEW ARTICLE

Quantitation of alpha-, beta-, and gamma-Kafirins in Vitreous and Opaque Endosperm of Sorghum bicolor.

J. J. Watterson, J. M. Shull, and A. W. Kirleis. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Landry-Moureaux fractionation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and enzyme-linked immunosorbent assays (ELISA) were used to investigate qualitative and quantitative differences in the protein compositions of vitreous and opaque endosperms of sorghum. Vitreous endosperm contained 1.5-2 times more protein than opaque endosperm of the same variety. Opaque endosperm contained more albumin-globulin protein and less kafirin, but the amount of glutelin protein was similar in both vitreous and opaque endosperm. The albumin-globulin fraction of opaque endosperm contained some higher molecular weight bands not seen in the albumin-globulin fraction of vitreous endosperm. The vitreous endosperm contained some lower molecular weight bands that did not appear in the opaque endosperm extracts. Both the SDS-PAGE gel of a total kafirin extract and the ELISA results indicated that the kafirin fraction of opaque endosperm has a higher percentage of beta- and gamma-kafirins and a lower percentage of alpha-kafirins compared to that of the kafirin fraction of vitreous endosperm. Because opaque endosperm had far less total kafirin than vitreous endosperm, total kafirin content may be more important than the protein-body composition in determining sorghum grain hardness.