This work is aimed at the determination of the kinetic and thermodynamic
properties of extracellular acid protease produced by
A. foetidus, which, to the best of our knowledge, has not been done
to date. Maximal activity was observed at pH 5.0 and 55 ◦C. Residual
activity tests carried out at 10–70 ◦C allowed estimating very long
enzyme half-lives (t1/2 = 37.74 h at 55 ◦C) as well as the thermodynamic
parameters of the irreversible denaturation of the enzyme.
Such event was characterized by an activation energy, Gibbs free
energy and enthalpy as high as 314.12, 111.7 and 311 kJ/mol and
an activation entropy of 601.9 J/mol K. These values as a whole
highlight an excellent thermostability of the enzyme that could be
profitably exploited for future industrial applications, especially in
the cosmetic and pharmaceutical sectors.