The solubilities of denatured proteins in different organic solvents

The solubilities of heat-denatured and reduced, S-carboxymethylated protein s have been investigated in various organic solvents. Polar, protic solvent s (formic acid, trifluoroacetic acid, 3-mercaptopropionic acid) were found to be good solvents for the denatured proteins (20-40 mg ml(-1)), and the s olubilities of the reduced, S-carboxymethylated proteins were generally hig her than those of the heat-denatured forms. Most other organic solvents wer e less effective in solubilising the denatured proteins. Apolar solvents di d not solubilise denatured proteins, but low solubilising powers were obser ved for polar, aprotic solvents. Heat-denaturation was observed to result in the formation of large intermol ecular aggregates, which, for ovalbumin and lysozyme, were formed by interm olecular S-S bonds, but for bovine serum albumin involved intermolecular is opeptide bonds.