TEMPERATURE SENSITIVITY AND PRESSURE RESISTANCE OF MUSHROOM POLYPHENOLOXIDASE

Measurements of residual enzyme activity and FTIR-spectroscopy reveale d that mushroom polyphenoloxidase is a thermosensitive enzyme readily inactivated by temperatures exceeding 50 degrees C. The enzyme is, how ever, very pressure stable. At room temperature no enzyme inactivation occurred at pressures up to 6 kbar. FTIR-spectroscopy revealed that a modification in enzyme conformation occurred below 9 kbar. Kinetic st udies showed that pressure and temperature did not always act synergis tically with respect to enzyme inactivation. FTIR-spectroscopy showed that pressure- or temperature-induced changes were considerably differ ent. Both temperature and pressure-temperature inactivation were only slightly influenced by pH (in the pH-range 5.5-7.5).