In order to better understand how to prevent enzymatic greenning, it is important to understand  kinetic properties of polyphenol oxidase.  we investigated the effect of SDS on the rate of catechol oxidation by small cherry tomato partial purified PPO. PPO activity increased with increasing SDS concentration. The most effective concentration of SDS was 0.8, 1 and 1.25 mM in according to pH and ...

Polyphenol oxidase (PPO) activity varied in differentiation from hyphae to rhizomorph and croute in A. mellea. In undifferentiated hyphae there was not any PPO activity, while croute showed the highest activity. Electrophoresis in the presence of SDS allows the detection of intensive enzyme forms of PPO, and can also convert slower migrating enzyme forms to faster ones. Some fluorescent co...

Polyphenol oxidase(PPO) (E.C. number 1.10.3.1) has ubiquitous distribution in almost all living organism. Whereas, peroxidase(POD) (E.C. number 1.11.1) act as hormone regulation and defense mechanism in plants. Keeping in pace with their present-day industrial application, efforts have been made to evaluate the activity of these two enzymes (PPO and POD) using pepper pericarp (Capsicum annuum L...

Polyphenol oxidase (PPO) from tomatoes was extracted and partially purified through  (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in solanum lycopersicum. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the ...

Polyphenol oxidases are found both in prokaryotic and eukaryotic microorganisms, in mammals, invertebrates and plants. Most plants have multiple forms of PPO. The more recent articles regarding the polyphenol oxidases from different plants are reviewed. The main characteristics considered were the sources, structure and properties of polyphenol oxidase (PPO) as well as the inhibitors of this en...

In terms of the quality of minimally processed fruit, flesh browning is fundamentally important in the development of an aesthetically unpleasant appearance, with consequent off-flavours. The development of browning depends on the enzymatic action of the polyphenol oxidase (PPO). In the 'Golden Delicious' apple genome ten PPO genes were initially identified and located on three main chromosomes...

Polyphenol oxidase (PPO) (E.C. 1.14.18.1) also known as phenolase, catechol oxidase, catecholase, monophenol oxidase, o-diphenol oxidase and orthophenolase based on their substrate specificity, is widely distributed in plants and fungi (Mayer, 2006; Kaur et al., 2010; Asha et al., 2011; Pawar and Ingle, 2014). PPOs have been purified and characterized from a wide range of plant species and a va...

Zhang X., Shao X. (2015): Characterisation of polyphenol oxidase and peroxidase and the role in browning of loquat fruit. Czech J. Food Sci., 33: 109–117. Polyphenol oxidase (PPO) and peroxidase (POD) were extracted from a new loquat fruit cultivar (Ninghaibai) and characterised using reliable spectrophotometric methods. In both cases, the optimum pH for PPO was 4.5 and 5 for POD, and their opt...

The ability of a number of mesoporous silica materials (SBA-15, SBA-3, and MCM-48) to immobilize polyphenol oxidase (PPO) at different pH has been tested. Pore size and volume are the structural characteristics with higher influence on the PPO immobilization. Mesoropous material SBA-15 adsorbs a larger quantity of PPO at pH 4.00 and offers an inhibition of enzymatic activity close the 50% in ap...

Esculetin has been described as an inhibitor of tyrosinase and polyphenol oxidase and, therefore, of melanogenesis. In this work, we demonstrate that esculetin is not an inhibitor but a substrate of mushroom polyphenol oxidase (PPO) and horseradish peroxidase (POD), enzymes which oxidize esculetin, generating its o-quinone. Since o-quinones are very unstable, the usual way of determining the en...