Modeling of Irreversible Thermal Protein Denaturation at Varying Temperature. I. The Model Involving Two Consecutive Irreversible Steps

A. E. Lyubarev^* and B. I. Kurganov

Bakh Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 117071 Russia; fax: (095) 954-2732; E-mail: inbio@glas.apc.org

^* To whom correspondence should be addressed.

Received November 13, 1997

---

The model of thermal protein denaturation involving two consecutive irreversible steps has been analyzed. The equation describing the dependence of excess heat capacity (C_p^ex) on temperature (T) under a constant scanning rate has been obtained and used for construction of theoretical C_p^ex versus T profiles. The change in the shape of theoretical profiles at varied Arrhenius equation parameters, ratio for enthalpies of the first and second steps, and the scanning rate have been studied. It has been shown that formal use of one-step model does not provide adequate information about kinetic features of the process in the case of protein denaturation following the mechanism involving two consecutive irreversible steps.

---

KEY WORDS: protein denaturation, differential scanning calorimetry, Arrhenius equation

---