The Effect of Hoffmeister Salts on the Chaperoning Action of β-Casein in Preventing Aggregation of Reduced β-Lactalbumin

Protein aggregation and precipitation is associated with many debilitating diseases including Alzheimer#039 s, Parkinson#039 s, and lightchain amyloidosis. βCasein, a member of the casein family, has been demonstrated to exhibit chaperonelike activity to protect protein form aggregation. Hofmeister salts (lyotropice series) are a class of ions which have an effect on the solubility and also the stability of proteins. In this study, using a range of Hofmeister salts (Na2SO4, NaCl and KSCN) altered the rate of aggregation and precipitation of αlactalbumin. The rate of aggregation of αlactalbumin increased in the presence of all the added salts. However, Na2SO4 had the greatest effect on the rate of aggregation of αlactalbumin. βCasein effectively prevented the aggregation of αlactalbumin but not as well as in the presence of the salt. Interestingly, in the presence of Na2SO4, βcasein was the poorer chaperone toward aggregation of αlactalbumin compare to in the presence of NaCl and KSCN. Our result showed that all salts had structural effects on the βcasein which affects its chaperone ability. In summary, structural change and kinetic factors maybe be determinant the poorer chaperone ability of βcasein in the presence of salts.