Study of thermal aggregation of globulin from common buckwheat (Fagopyrum esculentum Moench) by size-exclusion chromatography and laser light scattering

Document Type

Journal Article

Publication Date

2006

Keywords

Fagopyrum esculentum Moench, Buckwheat globulin, Thermal aggregation, Laser light scattering, Quasielastic light scattering

DOI

10.1021/jf052086r

Abstract

The heat-induced aggregation of common buckwheat (Fagopyrum esculetum Moench) globulin (BWG) was studied using size-exclusion chromatography (SEC) combined with on-line multiangle laser light scattering (MALLS) and quasielastic light scattering (QELS). The unheated BWG was found to exist mainly as a hexamer, with an estimated weight-average molecular weight (Mw) of 342 000, close to that deduced from the genomic cloned data of 13S buckwheat globulin. The QELS data predicted that the hexamer exists as two annular trimeric rings (diameter ∼ 10.8 nm) placed on top of each other, forming an oblate cylinder (height ∼ 9.1 nm). Upon heating, hexamers and trimers were dissociated and then associated to form extended small aggregates, finally forming compact, large macroaggregates. N-Ethylmaleimide would favor macroaggregate formation and increased the molar masses and hydrodynamic radii of the soluble aggregates, suggesting a different aggregation process in the presence of the sulfhydryl-blocking agent. A plot of log hydrodynamic radius versus log molar mass showed changes in the slope during heat treatment, suggesting conformational transformation in the heat-denatured and aggregated BWG molecules.

Source Publication

Journal of Agricultural and Food Chemistry

Volume Number

54

Issue Number

2

First Page

554

Last Page

561

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