Changes in the conformation of molecules - Qualitative Changes
You may recall that linear chain of amino acids of a protein folds into a characteristic structure. Acidic residues, glutamic and aspartic acids interact with basic residues, arginine and histidine and form ionic bonds. The thiols of cysteines form inter chain and intrachain disulphide (S-S) bridges which are very important for keeping the protein in desired conformation.
The extent of these interactions is influenced by the nature of the environment of protein. If most of the cysteines remain in the reduced state (-SH), there would be minimum folding. The unfolded state of protein molecule may not be as soluble and active as the folded conformation.