Amaranth, soybean and maize were screened for proteins and their nutritional value. Isopropanol-soluble protein and buffer-soluble protein fractions were extracted from seeds and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The comparison of the identity and differences between investigated plants was carried out by the obtained SDS-PAGE electrophoretic patterns, and their microstructure was determined by scanning electron microscopy. Electrophoretic patterns of extracted proteins have shown that the main protein subunits were concentrated between 10 and 50 kDa. Variations were found in major fractions and minor bands as well as in the fine structure. The microstructure of pseudocereal and cereal protein fractions was inter-related with the results obtained by their electrophoretic separation. Pseudocereal amaranth can be used as a nutritive substitute of cereal maize in functional foods.