The Dissociation of Proteins by Chaotropic Salts

Chaotropic salts were examined with a view to their use as protein-dissociating agents. The rank order of their ability to dissociate proteins followed the Hofmeister series for proteins which self-interact mainly via the formation of intermolecular hydrogen bonds (β-lactoglobulin A, hemoglobin). For hydrophobic associations (β-casein, concanavalin A, chymotrypsin), misplacements in the Hofmeister series were noted. Chaotropic salts do not necessarily bring about complete dissociation of protein polymer to protein monomer. However, dissociation was induced at salt concentrations which did not cause major shifts in protein conformation. Thus, chaotropic salts should prove most useful in dissociating multienzyme complexes and in improving the solubility of membrane-bound proteins.