First extraction of polyphenol oxidase from edible desert truffle (Terfezia leonis Tul.) and its thermal behavior

Polyphenol oxidase (PPO) is a common enzyme with large applications in food processing and analysis, especially based on their monophenolase activity. In this context, extraction and surfactant-mediated activation of PPO from desert truffle Terfezia leonis Tul. were successfully achieved. In the presence of l-tyrosine, the cresolase activity was optimal in the pH 5–6 domain and in the 35–45 °C temperature range. In the presence of pyrocatechol, the catecholase activity was optimal at neutral pH and 30 °C. Kinetics studies revealed higher affinity of PPO for l-tyrosine than for pyrocatechol. Both enzyme–substrate complexes were structurally robust, and their thermosensitivity was mainly related to entropy changes. These properties may reflect the adaptation to desert conditions where T. leonis grows and should be useful for the development of enzymatic catalysts and sensors.