Abstract
The seed proteins of linseed (Linum usitatissimum L.) were qualitatively and quantitatively analyzed. Qualitative studies were carried out using an array of electrophoretic techniques, including sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), sodium dodecylsulphate porosity gradient polyacrylamide gel electrophoresis (SDS-Poro-PAGE), two dimension sodium dodecylsulphate polyacrylamide gel electrophoresis (2-D SDS-PAGE), isoelectric focusing, and mapping gels. Electrophoretic patterns of the proteins extracted with water, buffer, urea, and SDS, and analyzed on SDS-PAGE and Poro-SDS-PAGE under non-reducing conditions, showed six major bands with MWs of 55 kDa, 50 kDa, 47 kDa, 45 kDa, 43 kDa and 41 kDa. After reduction with 2-mercaptoethanol (2-ME), these bands gave rise to large acidic chains with MWs around 40 kDa and small basic chains with MWs around 20 kDa. The pi-values of linseed proteins are distributed over the pH range used, namely pH 3-10. Mapping gels showed that the major bands were highly heterogeneous. Quantitative estimation of the different protein species in the seed flour indicated that the contents of albumin, globulin, prolamin, and glutelin were 197 +/- 19, 196 +/- 12, 32 +/- 7, and 65 +/- 6 mg/g seed flour, respectively.