Differential Scanning Calorimetry Study on Thermal Denaturation of Human Carbonic Anhydrase II

Abstract

The thermal unfolding of human carbonic anhydrase II (HCAII) has been studied by circular dichroism, UV−vis spectrophotometry, and differential scanning calorimetry (DSC). Coincidence of aggregation and tertiary structure disruption as well as fitting of DSC data showed that a two-state model can properly explain thermal unfolding of HCAII. According to this model, the average values of T * (the temperature at which k = 1/60 s −1 ), Δ H (enthalpy), and Δ E a (activation energy) are equal to 335.8 K, 698.6 kJ·mol −1, and 529.0 kJ·mol −1, respectively.