Denaturation of the high molecular weight protein fraction of mustard (Brassica juncea), and rapeseed (Brassica compestris) by urea or guanidinium hydrochloride.

Urea and guanidinium hydrochlOride dissociate the 12S protein of
mustard and rapeseed to 1.8 S protein and the extent of dissociation depends on the
concentration of the denaturant. Mustard (Bras$imjuncea) protein is more readily dissociated
than the rapeseed (Bras$im rompestrU) protein. The reagents denature the
protein as evidenced by increase in viscosity, appearance of difference spectra and
quenching of fluorescence. Rapeseed protein is denatured more readily than the
mustard protein. Analysis of viscosity, spectral and fluorescence data suggests that the
first event in the denaturation reaction is the perturbation of the aromatic amino acid
residues followed by their exposure to the solvent medium and unfolding of the protein
molecule.