Seed Storage Protein Extraction and Gel pH gradient for Cucumber Varietal Identification via an Ultrathin-Layer Isoelectric Focusing Technique

Abstract

A suitable seed protein extract solution and gel pH gradient for cucumber varietal identification via an ultrathin-layer isoelectric focusing (UTLIEF) technique were studied. Four seed protein extract solutions, namely; water, phosphate buffer, Na₂EDTA and NaCl in combination with 2 gel pH gradients of 2-11 and 4-5/3-10 were used with UTLIEF carried out on four commercial F-1 hybrid cucumber cultivars namely; Micro C, Big C, Chok-Dee and Bussaba. The results showed that the phosphate buffer solution dissolved most cucumber seed protein, resulting in the highest total protein concentration, followed by water solvent. Most polymorphic cucumber seed protein bands were focused in the pH range of 7-10. The pH gradient of 2-11 showed sharper and clearer protein bands than that of pH gradient 4-5/3-10. Water-extracted seed protein run on in a gel pH gradient of 2-11 had the most polymorphic protein band markers that could completely differentiate the four cucumber cultivars from each other.