Aspergillus aculeatus pectin methylesterase: study of the inactivation by temperature and pressure and the inhibition by pectin methylesterase inhibitor

The thermal inactivation kinetics of purified Aspergillus aculeatus pectin methylesterase (PME) was investigated. In the temperature range 46-56 °C A. aculeatus PME inactivates following a first-order reaction. Addition of CaCl2 (50 mM or 1.0 M) has no noticeable influence on the inactivation parameters. A. aculeatus PME is very pressure stable, at 25 °C no loss of activity was noticed after pressurization at 700 MPa for 1 h. Pressure and temperature exhibit an antagonistic effect on the enzyme stability. Furthermore A. aculeatus PME was unsusceptible for inhibition by PME inhibitor purified from kiwi.