Size characterisation of glutenin polymers by HPSEC-MALLS

The use of an on-line coupling of a new high-performance size exclusion chromatography (HPSEC) phase characterized by a very high exclusion limit and a multiangle laser light scattering detection (MALLS) for the size characterisation of wheat glutenin polymer was examined. Flour glutenin polymers which were extracted and purified by differential solubility in aqueous 50 and 70% propan-1-ol were solubilised with or without sonication in combination with a surfactant, 2%; SDS. The glutenin polymers of the two genotypes studied. Soissons (5 + 10, Glu-1D) and Thesee (2 + 12, Glu-1D), were characterised by large polydispersity and by significant difference of size distribution of total polymers. The molecular size distribution of the total polymers, which tan be used to differentiate the two genotypes. was highly correlated with the percentage of high-molecular glutenin subunits (HMV-GS) in glutenins. Furthermore, the results obtained for both the SDS-soluble and SDS-insoluble glutenin polymers from the two varieties revealed significant differences in size distribution, and also in molecular conformation (dependence of size upon mass). The molecular dimensions of SDS-insoluble polymers increased more slowly with the molecular weight than SDS-soluble polymers, which suggested a more compact structure. To conclude, the method appears to be a viable procedure to obtain rapid size characterisation of unreduced glutenin. (C) 2001 Academic Press.