title: Influence of pH, benzoic acid, EDTA, and glutathione on the pressure and/or temperature inactivation kinetics of mushroom polyphenoloxidase.
abstract: The pressure and/or temperature inactivation of mushroom polyphenoloxidase (PPO) in the absence and presence of EDTA, benzoic acid, and glutathione was studied on a kinetic basis. In addition, the effect of pH was evaluated. The temperature stability of PPO at atmospheric pressure increased with increasing pH up to pH 6.5. The pressure stability of PPO at room temperature (25 degrees C) also increased with increasing pH. EDTA slightly increased the thermal stability of the enzyme but did not alter the pressure stability of PPO. Benzoic acid protected the enzyme toward temperature but caused sensitization toward pressure when used at a concentration of 50 mM. Glutathione produced sensitization to both temperature and pressure. It is suggested that the sensitizing effect of glutathione is due to an interaction with a disulfide bond of the enzyme.
authors.affiliation: Department of Food and Microbial Technology, Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit Leuven, Belgium.
authors.forename: C A
authors.initials: CA
authors.lastname: Weemaes
authors.forename: S V
authors.initials: SV
authors.lastname: De Cordt
authors.forename: L R
authors.initials: LR
authors.lastname: Ludikhuyze
authors.forename: I
authors.initials: I
authors.lastname: Van den Broeck
authors.forename: M E
authors.initials: ME
authors.lastname: Hendrickx
authors.forename: P P
authors.initials: PP
authors.lastname: Tobback
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D001565:Benzoates / Q000494:pharmacology*; D019817:Benzoic Acid; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors* / Q000737:chemistry; D004492:Edetic Acid / Q000494:pharmacology*; D004795:Enzyme Stability; D005978:Glutathione / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011312:Pressure; D013696:Temperature
chemical_list: D001565:Benzoates; D019817:Benzoic Acid; D004492:Edetic Acid; D004156:Catechol Oxidase; D005978:Glutathione