Kinetics and Thermodynamics of the Thermal Inactivation of Polyphenol Oxidase in an Aqueous Extract from Agaricus bisporus
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- 作者：Hicham Gouzi ; Christophe Depagne ; Thibaud Coradin
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：January 11, 2012
- 年：2012
- 卷：60
- 期：1
- 页码：500-506
- 全文大小：273K
- 年卷期：v.60,no.1(January 11, 2012)
- ISSN：1520-5118
文摘
The kinetics and thermodynamics of the thermal inactivation of polyphenol oxidase (PPO) in an aqueous extract from mushroom Agaricus bisporus (J.E. Lange) Imbach was studied, using pyrocatechol as a substrate. Optimal conditions for enzymatic studies were determined to be pH 7.0 and 35鈥?0 掳C. The kinetics of PPO-catalyzed oxidation of pyrocatechol followed the Haldane model with an optimum substrate concentration of 20 mM. Thermal inactivation of PPO was examined in more detail between 50 and 73 掳C and in relation to exposure time. Obtained monophasic kinetics were adequately described by a first-order model, with significant inactivation occurring with increasing temperature (less than 10% preserved activity after 6 min at 65 掳C). Arrhenius plot determination and calculated thermodynamic parameters suggest that the PPO in aqueous extract from Agaricus bisporus mushroom is a structurally robust yet temperature-sensitive biocatalyst whose inactivation process is mainly entropy-driven.