Characterization of Sunflower Seed Proteins by Electrophoretic Techniques Reda Helmy Sammour*, M.N. EI-Shourbagy, A.M. Abo-Shady and A.M. Abasary Department of Botany, Faculty of Science, Tanta University, Tanta, Egypt ABSTRACT. The seed proteins of sunflower (Helianthus annuus) were qualitatively and quantitatively investigated. Qualitative studies were carried out using different electrophoretic techniques (SDS-PAGE, Poro-PAGE, 2-D SOS-PAGE, lsoelectric focusing, Mapping gels). Analysis of the water extracted flour on SOS-PAGE and SDS-Poro-PAGE gave five major polypeptides with MWs of 63.5 KD, 60 KO, 58 KD, 55 KO and 51 KO. The pattern of the buffer extract exhibited 8 major polypeptides with MWs of 65.5 KO, 63.5 KO, 60 KD, 58 KD, 55 KD, 54 KO, 51 KD and 42.5 KO. Second dimension gel showed that the polypeptides with MWs of 65.5 KO, 60 KO, 58 KO, 55 KD, 54 KD, 51 KD are legumin-like proteins. Isoelectric points of the majority of the sunflower seed proteins were between 5 and 7. Mapping gels, however, showed that sunflower seed proteins were highly heterogeneous, especially the major bands. A quantative study indicated that the albumin, globulin, prolamin and glutelin fractions amounted 38.32%, 39.04%, 5.53% and 17.09% respectively of the extracted proteins. f\ I . i ~ J Oilcrops have a world importance. Some of them are directly used as food, while most of them are utilized to obtain fats or oils and cake or flour (Lennerts 1984, Hatje 1989). Sunflower (Helianthus annuus) is an annual oilcrop (belonging to the family Compositae (Lennerts 1984». The defatted flour of sunflower is used as a source of highly digestible and nutritive protein for poultry (Smith 1968). ,Key words: Sunflower seed globulin, Helianthus annuus; molecular weights (MWs); two dimension-PAGE (2-D SOS-PAGE); SDS (Sodium Dodecyl Sulphate); 2-ME (2-mercaptoethanol). * Correspondinb Author.