the electrochemistry of banana tissues on a carbon paste electrode modified with multi-walled carbon nanotubes (mwcnts) is presented. cyclic voltammetry is applied to investigate the direct electrochemistry of banana tissues i.e. a source of polyphenol oxidase (ppo). a redox couple with an anodic and counterpart cathodic peak is obtained. the influence of various parameters such as ph, scan rat...

trehalose is an important disaccharide signal metabolite in plants which is involved in various aspects of plant function such as response to stress, photosynthesis and carbon allocation and partitioning. a mutant of arabidopsis lacking trehalose-6-phosphate synthase activity (tps1) accumulates ascorbate. exogenous ascorbate application ameliorates trehalose induced growth inhibition of wild ty...

Alternative oxidase (AOX) has been documented to mitigate the oxidative stress caused by abiotic stresses. However, it remains unknown how AOX regulates antioxidant system and photosynthesis under waterlogging. To address this issue, we used two watermelon (Citrullus lanatus L.) cultivars (waterlogging tolerant cultivar ‘YL’ sensitive ‘Zaojia8424’) as materials inhibitor salicylhydroxamic acid ...

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 ...

Reactive oxygen species (ROS) play an active role in plant defense. Polyphenol oxidase (PPO) and peroxidase (POD) participate the synthesis of phytoalexins. The comparative activities ROS, including hydrogen peroxide (H2O2), superoxide anions (O2−), hydroxyl radicals (·OH), against fungal pathogen Colletotrichum gloeosporioides from papaya fruit were evaluated. effects ROS on PPO POD inoculated...

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 ...

KOCAQALISKAN I., DEMIR Y. & KABAR, K. 1995. A study on polyphenol oxidase activity during seed germination. Phyton (Horn, Austria) 35 (1): 37-43. English with German summary. In this work, polphenol oxidase (PPO) activities, when used four different substrates (dopa,catechol,caffeic acid, tyrosine) oxidizing activities, during seed germination of six different plants were studied in the embryos...

This work evaluated the enzymatic and non-enzymatic antioxidant defense systems of avocados cv. Hass stored at 7 ± 0.5 °C for 10, 20, 30 d, stage edible ripeness. The enzyme system included superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), was composed total phenolic compounds (TPC), carotenoids (TC), α-, β-, γ-tocopherols, as well hydrophilic (H-AOX) lipophilic (L-AOX) activities. ...

Aril browning threatens production, consumption, and exports of pomegranates, because affected fruit cannot be externally distinguished from healthy fruit. This study compared the mineral, biochemical composition, and related enzyme activities in affected brown arils with healthy ones in ‘Malase Saveh’ pomegranates. The results indicated that concentrations of Cu in the aril and K, Mg, and Mn i...

background & aim: glycyrrhiza l. (fabaceae) consists of perennial herbs grow in sandy soils with hard lightness. three species of the genus grow in iran, among them g. glabra l. has the widest distribution. it is well known in english as licorice and the root extract includes flavonoids and glycyrrhizin are used widely in medicine, food industry, tobacco products and other industries. liqui...