Chemistry and Biochemistry: Research Progress Vol. 12

Thermal stability is a pivotal parameter in evaluating the biotechnological potential of enzymes. The objective of this study is to characterise, from a thermodynamic perspective, the thermal behaviour of an acid phosphatase extracted from the seeds of Artocarpus communis. The experimental data on thermal inactivation, obtained in the presence of p-nitrophenyl phosphate (pNPP), were subjected to re-analysis using an equilibrium model (EQM) describing the reversible transition between an active and an inactive form of the enzyme, followed by irreversible thermal inactivation. This methodological approach enabled the quantitative description of the evolution of enzymatic activity as a function of temperature and time, and the estimation of the thermodynamic parameters associated with the catalytic and inactivation processes. The values obtained for the free energies of activation for catalysis and inactivation were 83.37 ± 0.02 kJ mol⁻¹ and 101.9 ± 0.2 kJ mol⁻¹, respectively. The equilibrium enthalpy and equilibrium temperature were estimated at 185 ± 2 kJ mol^-1 and 326.90 ± 0.16 K, respectively. The relatively high value of the free energy associated with inactivation indicates the enzyme's good resistance to thermal destabilisation. The maximum level of activity was observed within a temperature range of approximately 315 to 330 K, while a sustained increase in temperature resulted in a gradual decline in activity. The findings demonstrate that the equilibrium model provides a pertinent framework for the thermodynamic analysis of the thermal stability of the acid phosphatase from A. communis and for the identification of parameters that are useful for evaluating its potential in biotechnology.