Determination of enzymatic reaction enthalpy by simultaneous calorimetry and spectrophotometry

作者:Zhang, Cheng-nan; Yuan, Min; Wei, Yan; Xu, Fei*; Yu, Jin-song; Cao, Hui
来源:Journal of Thermal Analysis and Calorimetry, 2015, 120(1): 283-288.
DOI:10.1007/s10973-014-3819-y

摘要

A synchronized calorimetric and spectrophotometric method for measuring enzymatic reaction enthalpy was described. The spectrophotometric method was used to determine the amounts of reactant or product changes during the reaction, and calorimetry was used to determine the thermal changes associated with the reaction. Both methods used a same reaction system to simultaneously measure the progress of reaction. By the synchronized calorimetric-spectrophotometric determination, enthalpy values were obtained as 92.17 +/- A 3.06 kJ mol(-1) by the initial velocity calculation method and 100.9 +/- A 1.81 kJ mol(-1) by the steady-state calculation method for a catalase-catalyzed hydrogen peroxide reaction at 298.15 K and pH 7.0. When comparing with the theoretical values, the results showed that the synchronized method with the steady-state method was in alignment and demonstrated greater stability.