Molecular weight determination of gliadin fractions in gel filtration by SDS-polyacrylamide gel electrophoresis and sedimentation equilibrium.

Abstract

Gliadin was fractionated into three fractions; ω-gliadin, Fraction III (γ-gliadin) and Fraction IV (α- and β-gliadin). The determination of the molecular weights (MW) of the three fractions was performed by both SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and sedimentation equilibrium. In SDS-PAGE, ω-gliadin gave three bands (MW 50, 000, 54, 000 and 64, 000), Fraction III two bands (MW 38, 000 and 46, 000) and Fraction IV two bands (MW 33, 000 and 38, 000). The sedimentation analysis showed that each fraction was fairly homogeneous relative to molecular weight. The molecular weights obtained by sedimentation were 28, 000 for Fraction III and 27, 000 for both Fraction IV and ω-gliadin. The disagreement in molecular weight between sedimentation and gel electrophoresis was discussed.