Extraction, Fractionation and Characterization of Cotton (Gossypium herbaceum L.) Seed Proteins

Protein fractions (water-soluble/albumin, salt-soluble/globulin, alkali-soluble/glutelin, and alcohol-soluble/prolamin) were extracted from fifteen cotton (Gossypium herbaceum L.) genotypes defatted seed using water, 0.5 M sodium chloride solution, alkali/pH 11.0, and 70% ethanol, sequentially. The main protein fraction was water soluble albumin (40.6 to 56.29%) followed by globulin (21.69 to 42.78%), glutelin (4.8 to 34.7%) and prolamin (0.81 to 2.47%) among the genotypes. Genotype Gv Hv 715 contained high albumin, Bagasara ghed selection contained high glutelin whereas A.D.C-1 contained high globulin and prolamin. The molecular size of the albumin and glutelin fractions was 20 to 55 kDa whereas globulin was 20 to 125 kDa. No prolamin was detected on gel. Cotton seed protein fractions with unique protein profiles could impart characterization of different cotton genotypes.