Differential Scanning Calorimetry to Quantify Heat-Induced Aggregation in Concentrated Protein Solutions

: Differential scanning calorimetry (DSC) is an important technique to measure the thermodynamics of protein unfolding (or folding). Information including the temperature for the onset of unfolding, the melt transition temperature (Tm), enthalpy of unfolding (ΔH), and refolding index (RI) are useful for evaluating the heat stability of proteins for a range of biochemical, structural biology, industrial, and pharmaceutical applications. We describe a procedure for careful sample preparation of proteins for DSC measurements and data analysis to determine a range of thermodynamic parameters. In particular, we highlight a measure of protein refolding following complete thermal denaturation (RI), which quantifies the proportion of protein lost to irreversible aggregation after thermal denaturation.