Effect of high-pressure treatment on the molecular properties of mushroom polyphenoloxidase

Abstract

To elucidate the mechanism of pressure-induced denaturation of mushroom polyphenoloxidase (PPO), the enzyme was treated under 600 and 800 MPa, respectively, and its molecular properties such as secondary and tertiary structure were examined. High-pressure inactivation of the enzyme increased with pressure level and treatment time. Circular dichroism study showed that high-pressure treatment decreased the negative ellipticity values in the range 210-225 nm, resulting in change of the secondary structure of the enzyme. Fluorescence emission intensities also decreased with increase of high pressure and processing time, indicating changes in the tertiary structure of the enzyme. This study clearly shows that high-pressure treatment significantly alters the molecular properties of the enzyme. © 2002 Elsevier Science Ltd. All rights reserved.