Some Kinetic Properties of Polyphenol Oxidase Obtained from Various Salvia Species (Salvia Viridis L., Salvia Virgata Jacq. and Salvia Tomentosa Miller)

2003 ◽  
Vol 9 (4) ◽  
pp. 309-315 ◽  
Author(s):  
G. Gundo[notdef]ggmaz ◽  
S. Do[notdef]ggan ◽  
O. Arslan
Keyword(s):  
Ascorbic Acid ◽  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Arrhenius Equation ◽  
Activation Energies ◽  
Kinetic Properties ◽  
Acid Activation ◽  
Effective Inhibitor ◽  
Polyphenol Oxidase Activity

Polyphenol oxidase (PPO) was partially purified by (NH4)2SO4 precipitation followed by dialysis from different organs of Salvia species (Salvia virgata Jacq., Salvia viridis L. and Salvia tomentosa Miller). Polyphenol oxidase activity was measured spectrophotometrically at 420 nm using catechol as a substrate. Vmax, KM and Vmax/KM values for polyphenol oxidase activity from different organs of Salvia species were determined. S. tomentosa Miller was the species with the highest PPO activity, followed by S. virgata Jacq and S. viridis L. S. tomentosa Miller was the most suitable Salvia species for dark-tea preparations because of the highest Vmax/KM values. The effects of various inhibitors on the reaction catalysed by the enzyme were tested and calculated I50 values, reduced the enzyme activity by 50%. The most effective inhibitor was L-cysteine followed by ascorbic acid. Activation energies, Ea, were determined from Arrhenius equation.

scholarly journals Enzyme activity in banana fruits rotted by Botryodiplodia theobromae Pat.

2015 ◽  
Vol 31 (1–2) ◽  
pp. 41-46
Author(s):  
Nityananda Chakraborty ◽  
Balen Nandi
Keyword(s):  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Botryodiplodia Theobromae ◽  
Polyphenol Oxidase Activity

Peroxidase and polyphenol oxidase activities in fruits of two cultivars of banana, 'champa' and 'kanthali' rotted by <i>Botryodiplodia theobromae</i> Pat. was studied. The enzymes showed much higher activities in infected than that in uninfected 'tissues. Increase in peroxidase activity was evidently inhibited by cycloheximide. Polyphenol oxidase activity was also inhibited in presence of phenylthiourea and Na-diethyldithiocarbamate more strongly by the former. Increase in activities seemed to be due to increased sytheses of the enzymes. In an <i>in vitro</i> culture, the fungus exhibited some peroxidase but no polyphenoloxidase activity.

scholarly journals MEKANISME INHIBISI ENZIM POLIFENOL OKSIDASE PADA SARI BUAH MARKISA DENGAN SISTEIN DAN ASAM ASKORBAT1

2015 ◽  
Vol 4 (2) ◽  
pp. 32
Author(s):  
Elida Mardiah
Keyword(s):  
Ascorbic Acid ◽  
Enzyme Inhibition ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Polyphenol Oxidase Activity ◽  
Optimum Activity ◽  
Oxidase Enzyme

 ABSTRACT The mechanism of polyphenol oxidase enzyme inhibition was studied by isolation of enzyme from the passion fruite juice (Passiflora Sp). The extracted enzyme polyphenol oxidase has an optimum activity at pH 5,6 and temperature of 300 C using a pirogalol substrate. The pattern of inhibition of the enzyme polifenol oxsidase studied using cysteine and ascorbic acid. Cystein of 10 mM consentration can inhibit the enzyme polyphenol oxidase activity as 97.25%, ascorbic acid with the same concentration can inhibit the enzyme polyphenol oxsidace 96.5%. The pattern of inhibition of cysteine is more likely to be competitive, while non-competitive with ascorbic acid. Keyword: polyphenol oxsidase, inhibition, cysteine, ascorbic acid

scholarly journals Biochemical changes in pear (Pyrus communis L. depending on different phases of the dormancy

2004 ◽  
Vol 10 (3) ◽  
Author(s):  
M. Göndör ◽  
K. Honty ◽  
A. Pedryc ◽  
I. Hajdrik ◽  
É. Stefanovits-Bányai
Keyword(s):  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Developmental Stages ◽  
Frost Tolerance ◽  
Biochemical Changes ◽  
Polyphenol Oxidase Activity ◽  
Pyrus Communis L ◽  
Artificial Freezing ◽  
Frost Injuries

Pear cultivars of variable frost tolerance were tested as for frost injuries suffered as a consequence of artificial freezing temperatures during the endodormancy as well as the ecodormancy. Damages were registered according to a visually defined scale, then peroxidase and polyphenol-oxidase activity was checked in buds, spurs and limbs. According to our results, 'Packham's Triumph' was the most frost tolerant cultivar. Regarding enzyme activity of both enzymes, the performance of cultivars displaying different susceptibility was also different in spurs as well as in buds. Results referring to the endodormancy were especially instructive. During the ecodormancy, data obtained at the same time indicated the differences existing between the developmental stages of dormancy in the respective cultivars.

scholarly journals Effect of antioxidants and pH on browning and firmness of minimally processed eggplant

2020 ◽  
Vol 48 (1) ◽  
pp. 79-89
Author(s):  
Diana P. USCANGA-SOSA ◽  
María B. PÉREZ-GAGO ◽  
Fernando C. GÓMEZ-MERINO ◽  
José A. HERRERA-CORREDOR ◽  
Aleida S. HERNÁNDEZ-CÁZARES ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Storage Period ◽  
Visual Quality ◽  
Minimally Processed ◽  
Polyphenol Oxidase Activity ◽  
Minimal Processing ◽  
Visual Evaluation

Minimal processing of eggplant (Solanum melongena L.) generates loss of firmness and polyphenol oxidase catalyzes the oxidation of phenolic compounds producing enzymatic browning. The aim of this study was to evaluate the effect of 1% ascorbic acid and 2% calcium ascorbate in aqueous solution at natural pH of the antioxidant (pH 2.6 and 7.8, respectively), or adjusted to pH 5 with generally recognized as safe substances, mantaining the quality of minimally processed eggplant stored at 5 °C for 6 d. Water was used as a control. The color, firmness, polyphenol oxidase activity, and visual quality was evaluated in the freshly cut fruit at 3 and 6 d of storage. No effect of the treatments on firmness or polyphenol oxidase activity was observed. At 3 d of storage, a correlation was observed between polyphenol oxidase activity and the visual evaluation of the cut product. Samples treated with 2% calcium ascorbate and the rest of the treatments at pH 5 had a lower browning index than those treated with 1% ascorbic acid and the control. At the end of the storage period, the visual quality of the eggplant samples treated with 1% ascorbic acid at pH 5 was evaluated above the marketing limit, whereas those treated with 1% ascorbic acid at pH 2.6 had the lowest quality indicators. An adjustment to pH 5 helps to preserve the luminosity and visual quality of the eggplant, however firmness was not affected by calcium ascorbate or the pH of the medium.

Plant age affects elicitation of polyphenol oxidase activity by neem extract in Solanum lycopersicum against Pseudomonas syringae pv. tomato

2015 ◽  
Vol 62 (4) ◽  
pp. 283-293 ◽  
Author(s):  
Navodit Goel ◽  
Prabir Kumar Paul
Keyword(s):  
Enzyme Activity ◽  
Pseudomonas Syringae ◽  
Polyphenol Oxidase ◽  
Azadirachta Indica ◽  
Oxidase Activity ◽  
Plant Age ◽  
Polyphenol Oxidase Activity ◽  
Neem Extract ◽  
Defense Enzyme ◽  
The Impact

Polyphenol oxidase (PPO) is a key defense enzyme widely distributed in the plant kingdom. The enzyme has been reported to be inducible by biotic inducers. The present study instigated the impact of plant age on induction of activity of PPO and pattern of isoenzymes by aqueous fruit extracts of Azadirachta indica (neem). The study involved the host–pathogen system of tomato (F1 tomato, Roopsi variety, Century seeds) and Pseudomonas syringae pv. tomato. Plants of 6, 8, 10 and 12 weeks of age were used for the study. Samples were collected 0, 24, 48, 72, 96 hours and 2 weeks post treatment. The results demonstrated that plant age impacts the expression and inducibility of PPO in tomato. Neem extract does not significantly inhibit the growth of Pseudomonas syringae pv. tomato. Therefore, the reduction in disease severity in neem-treated plants is related to changes in the activity of PPO in the host plant. The 10-week-old plants had significantly highest PPO activity as compared to 12-week-old plants, which had the lowest enzyme activity. Consequently, the 10-week-old plants were more resistant to the pathogen among all the ages studied. The distal untreated leaves or the leaves emerging after neem treatment were also significantly resistant to the pathogen. Treatment with neem prior to pathogen inoculation was more effective in priming the plants. The neem extract induced the defense response in tomato primarily through upregulation of the PPO gene.

scholarly journals Biochemical changes in pear (Pyrus communis L. depending on different phases of the dormancy

2004 ◽  
Vol 10 (3) ◽  
Author(s):  
Göndör M. ◽  
Honty K. ◽  
Pedryc A. ◽  
Hajdrik I. ◽  
Stefanovits-Bányai É.
Keyword(s):  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Developmental Stages ◽  
Frost Tolerance ◽  
Biochemical Changes ◽  
Polyphenol Oxidase Activity ◽  
Pyrus Communis L ◽  
Artificial Freezing ◽  
Frost Injuries

Pear cultivars of variable frost tolerance were tested as for frost injuries suffered as a consequence of artificial freezing temperatures during the endodormancy as well as the ecodormancy. Damages were registered according to a visually defined scale, then peroxidase and polyphenol-oxidase activity was checked in buds, spurs and limbs. According to our results, 'Packham's Triumph' was the most frost tolerant cultivar. Regarding enzyme activity of both enzymes, the performance of cultivars displaying different susceptibility was also different in spurs as well as in buds. Results referring to the endodormancy were especially instructive. During the ecodormancy, data obtained at the same time indicated the differences existing between the developmental stages of dormancy in the respective cultivars.

Pectin-based edible coating preserves antioxidative capacity of plum fruit during shelf life

2020 ◽  
Vol 26 (7) ◽  
pp. 583-592 ◽  
Author(s):  
Sima Panahirad ◽  
Rahim Naghshiband-Hassani ◽  
Nasser Mahna
Keyword(s):  
Ascorbic Acid ◽  
Shelf Life ◽  
Polyphenol Oxidase ◽  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Edible Coating ◽  
Total Phenolic ◽  
Antioxidative Capacity ◽  
Three Solutions ◽  
Polyphenol Oxidase Activity

Exploiting safer methods for fruit preservation such as application of edible coatings can improve shelf life, valuable characteristics, and antioxidative capacity. The current study aimed to investigate the effect of a pectin-based edible coating on antioxidative capacity of plum fruit during shelf life (19 ± 2 ℃ and 65% relative humidity for eight days). To do this, three solutions (0.5, 1, and 1.5%) of pectin, plasticized by glycerol (0.3% w/v), were applied on plum fruit and compared to a control treated with only distilled water. Ascorbic acid, total phenolics, anthocyanin and flavonoid contents, total antioxidative capacity based on 1,1-diphenyl-2-picryl-hydrazyl hydrate method, peroxidase (as an antioxidant enzyme), and polyphenol oxidase (as an oxidant enzyme) activities were recorded during this period. The results demonstrated that pectin-based edible coating was significantly effective on maintaining ascorbic acid, anthocyanin and flavonoid contents, and antioxidative capacity in plum fruits (P ≤ 0.01). The activities of enzymes were significantly affected by the coatings; peroxidase activity increased and polyphenol oxidase activity decreased (P ≤ 0.01). All pectin concentrations significantly caused higher ascorbic acid and anthocyanin contents, antioxidative capacity, and peroxidase activity but a lower polyphenol oxidase activity than the control; however, just 1 and 1.5% concentrations were effective in terms of total phenolic compounds and flavonoid content, respectively, and the other concentrations acted the same as the control. In general, the coating constituted from 1.5% pectin showed the best results for most measured parameters. Considering the influences of pectin-based edible coating on antioxidative characteristics of plum fruits, its application can be potentially regarded as a favorable method to enhance nutritional value of fruits.

Sign in / Sign up

Export Citation Format

Share Document