EFFECTS OF MEDIUM AND CHEMICAL MODIFICATION ON THERMAL-CHARACTERISTICS OF BETA-LACTOGLOBULIN

The thermal properties of beta-lactoglobulin (beta-LG) were studied by differential scanning calorimetry (DSC) under different medium condit ions, pH, neutral salts, protein perturbants, and polyols all affected the DSC characteristics of beta-LG. Acylation with fatty acids also c hanged the thermal properties, particularly peak width at half-height. The results suggest that the structural stability of beta-LG is contr olled by non-covalent forces, particularly electrostatic and hydrophob ic interactions. Disulfide bonds did not contribute to the thermal res ponse of beta-LG. Fatty N-acylamino acids caused marked increases in t hermal stability and decreases in denaturation enthalpy, and additiona l peaks were observed in the presence of some palmitoyl derivatives.