What can we get from varying scan rate in protein differential scanning calorimetry

Abstract Differential scanning calorimetry has many advantages over other techniques to study the thermal stability of proteins due to its direct measurement of thermodynamic parameters. Most proteins undergo irreversible thermal denaturation causing their thermogram to be scan rate dependent. We modeled reversible and irreversible protein thermograms at varying scan rates. The complete Lumry-Eyring model was used to model the irreversible thermograms at various values of T 1/2 (temperature at which equilibrium constant equals unity) and T * (temperature at which rate constant equals 1 min −1 ). Our results have shown that the thermal effects of two processes are integrated with decreasing the T * relative to T 1/2 . It is also shown that the shape of second derivatives of thermograms under different conditions have specific pattern which can be used to judge and estimate the correct model for protein denaturation.