The Hofmeister effect as seen by SAXS in protein solutions

Protein interactions in solution are conveniently analysed with small angle X-ray scattering (SAXS). Such an analysis has shown that the addition of monovalent salt induces an additional attraction between macromolecules. A differential effect of the anions is observed, which follows the order of the Hofmeister series. Such experimental observations should be helpful to test the adequacy of theoretical models.