Thermal Denaturation of
Pea Globulins (<i>Pisum
sativum</i> L.)Molecular Interactions Leading to Heat-Induced
Protein Aggregation
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Abstract
The heat-induced denaturation and aggregation of mixed
pea globulins
(8%, w/w) were investigated using differential scanning calorimetry
(DSC), SDS-PAGE, and size-exclusion chromatography (SEC-HPLC). DSC
data showed that the pea proteins denaturation temperature (<i>T</i><sub>d</sub>) was heating-rate dependent. The <i>T</i><sub>d</sub> value decreased by about 4 °C by lowering the heating
rate from 10 to 5 °C/min. The SDS-PAGE analysis revealed that
protein denaturation upon heating at 90 °C was mainly governed
by noncovalent interaction. The SEC-HPLC measurements indicated that
low-denatured legumin (≈350–410 kDa) and vicilin/convicilin
(≈170 kDa) globulins were heat-denatured and most of their
subunits reassociated into high-molecular weight, soluble aggregates
(>700 kDa). The addition of <i>N</i>-ethylmaleimide slightly
modified the aggregation route of pea globulins. However, partially
insoluble macroaggregates were produced in the presence of dithiothreitol,
reflecting the stabilizing effect of disulfide bonds within legumin
subunits