This paper reports the thermokinetic models of single-substrate, enzyme-catalyzed reactions occurring in batch and plug-flow reactors, respectively. By analyzing the calorimetric curves of these reactions, these models can be used to produce not only the thermodynamic data (Delta(r)H(m)) but also the kinetic data (K-m and k(2)) Using a LKB-2107 batch microcalorimeter and an LKB-2277 Bioactivity Monitor, the catalase-catalyzed decomposition of hydrogen peroxide was studied and its molar reaction enthalpy (Delta(r)H(m)) measured as -88.88+/-0.6 kJ mol(-1). The Michaelis constant (K-m) for H2O2 was determined by the batch and plug-flow thermokinetic models to be 5.03+/-0.18x10(-3) mol dm(-3) and (5.27+/-0.11)x10(-3) mol dm(-3), respectively. The reliability of these models for determination of the thermokinetics of single-substrate, enzyme-catalyzed reactions occurring in these two types of reactors was verified by the experimental results.