Two-dimensional gel electrophoresis of zein proteins from normal and opaque-2 maize with non-ionic detergent acid urea-polyacrylamide gel electrophoresis in the first dimension

Two-dimensional electrophoresis of cereal prolamins: applications to biochemical and genetic analyses

Three complementary two-dimensional systems for the analysis of cereal prolamins are described. These are electrophoresis at pH 3.1 followed by electrophoresis at pH 9.2, isoelectric focusing (IEF) followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-PAGE under non-reducing conditions followed by SDS-PAGE with reduction. They together give information on the pIs, Mrs and charge properties of the individual prolamin components, and on their interactions to form oligomers stabilized by inter-chain disulphide bonds. The three systems are then compared for their effectiveness in analysing unreduced prolamin I fractions from wheat and rye, and the IEF/SDS-PAGE system for analysing reduced and pyridylethylated prolamin fractions from all the major cereals. Finally, applications of the systems in biochemical and genetic studies are discussed and illustrated with three examples: analysis of the structural relationships of the S-rich prolamins (B hordeins and gamma-type hordeins) of barley, determination of the interactions of wheat and rye prolamin subunits in a 2RS/2BL translocation line, and the mapping of genes for alpha-type prolamins in the wild grass Haynaldia villosa.

The use of two-dimensional gel electrophoresis in the analysis of organ-specific maize proteins

Two-dimensional gel electrophoresis with non-equilibrium pH gradient electrophoresis in the first dimension and sodium dodecyl sulfate-polyacrylamide gels in the second dimension has been used for the analysis of organ-specific proteins in maize. The method has been used to study the whole protein pattern of developing organs and adult leaves as well as protein patterns of in vitro translation. Examples of two-dimensional immunoblotting and in vitro translation of endosperm-specific proteins are also shown. Two-dimensional gel electrophoresis appears as an essential analytical step in the identification of organ-specific proteins and for the detection of the protein products related to organ-specific genes identified by other means.