Effect of sodium dodecyl sulphate on the high molecular weight protein fraction of mustard (Brassica juncea) and rapeseed (Brassica campestris).

The effect of sodium dodecyl sulphate on mustard and rapeseed 12 S protein
has been monitored by the techniques of uitracenrrifugation, viscosity, difference
spectra and fluorescence spectrophotometry. At low concenrration of sodium dodecyl
sulphate « 3.47 mM) mustard protein undergoes aggregation and at higher concentrations
it dissociates (0 1.8 S protein, the dissociation being complete at 17.3 mM. sodium
dodecyl sulphate. The rapeseed protein, on the other hand, undergoes dissociation
at all the concentrations of sodium dodecyl sulphate. The reduced viscosity values or
mustard protein in the presence of the denaturant are higher than those of rapeseed
protein. Similarly in difference spectra change in absorbance values of mustard protein
are higher:The relative fluorescence intensity of the mustard protein increases with
sodium dodecyl sulphate concentration, upto 0.87 mM and this is followed by
fluorescence quenching at higher denaturant concentrations. However, with the rapeseed
protein fluorescence quenching was observed at all concentrations of sodium
dodecyl sulphate.