Some kinetic properties of polyphenol oxidase obtained from dill (Anethum graveolens)
Authors:
Open Access
- 1 January 2008
- journal article
- research article
- Published by Taylor & Francis in Journal of Enzyme Inhibition and Medicinal Chemistry
- Vol. 23 (3) , 380-385
Abstract
Polyphenol oxidase (PPO) was partially purified from dill by (NH4)2SO4 precipitation followed by dialysis and gel filtration chromatography. Polyphenol oxidase activity was measured spectrophotometrically at 420 nm using catechol, dopamine and chlorogenic acid as substrates. Optimum pH, temperature, and ionic strength were determined with three substrates. The best substrate of dill PPO was found to be chlorogenic acid. Some kinetic properties of the enzyme such as Vmax, KM and Vmax/KM were determined for all three substrates. The effects of various inhibitors on the reaction catalysed by the enzyme were tested and I50 values calculated. The most effective inhibitor was l-cysteine. Activation energies, Ea, were determined from the Arrhenius equation. In addition, activation enthalpy, ΔHa, and Q10 values of the enzyme were also calculated.Keywords
This publication has 58 references indexed in Scilit:
- Polyphenol oxidases in plants and fungi: Going places? A reviewPhytochemistry, 2006
- Content of vitamin C, carotenoids, chlorophylls and polyphenols in green parts of dill (Anethum graveolens L.) depending on plant heightJournal of Food Composition and Analysis, 2006
- Fungal tyrosinases: new prospects in molecular characteristics, bioengineering and biotechnological applicationsJournal of Applied Microbiology, 2006
- Reaction mechanism to explain the high kinetic autoactivation of tyrosinaseJournal of Molecular Catalysis B: Enzymatic, 2005
- Tyrosinase kinetics: discrimination between two models to explain the oxidation mechanism of monophenol and diphenol substratesThe International Journal of Biochemistry & Cell Biology, 2004
- Monophenolase and Diphenolase Reaction Mechanisms of Apple and Pear Polyphenol OxidasesJournal of Agricultural and Food Chemistry, 1998
- Oxidation of Chlorogenic Acid, Catechins, and 4-Methylcatechol in Model Solutions by Combinations of Pear (Pyrus communis Cv. Williams) Polyphenol Oxidase and Peroxidase: A Possible Involvement of Peroxidase in Enzymatic BrowningJournal of Agricultural and Food Chemistry, 1997
- Occurrence and distribution of ppo activity in floral organs of some standard and local cultivars of teaJournal of the Science of Food and Agriculture, 1994
- Enzymatic browning of foodsEuropean Food Research and Technology, 1983
- Food Browning as a Polyphenol Reaction1971