Wyniki wyszukiwania

1

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Kinetics properties of polyphenol oxidase in hawthorn (Crataegus spp.)

100%

Saeidian S.

International Letters of Natural Sciences

|

2014

|

tom 20

Polyphenol oxidase (PPO) from hawthorn was extracted and partially purified through (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in Crataegus spp. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the substrates tested, catechol was the best substrate for PPO with a Km value of 2.2 mM. The optimum pH for PPO activity was found to be 7. The enzyme showed high activity over a broad pH range of 4 - 8. The optimal pH and temperature for enzyme activity were found to be 7 and 40-45 °C, respectively. km value for hawthorn PPO is calculated 22 mM for catechol and 6.7 mM for pyrogallol and 9.7 mM for L-dopa. As can be seen, affinity of PPOs for various substrates varies widely. The enzyme showed a broad activity over a broad pH and temperature range. The thermal inactivation studies showed that the enzyme is heat resistant. The enzyme showed the highest activity toward pyrogallol and no activity toward tyrosine. Of the inhibitors tested, the most potent inhibitors were kojic acid, cysteine and glycine , respectively.

2

Indirect inactivation of tyrosinase in its action on tyrosine

100%

Munoz-Munoz J. L., Garcia-Molina F., Acosta-Motos J. R., Arribas E., Garcia-Ruiz P. A., Tudela J., Garcia-Canovas F., Rodriguez-Lopez J. N.

Acta Biochimica Polonica

|

2011

|

tom 58

|

nr 4

Under aerobic conditions, tyrosinase is inactivated by dopa as a result of suicide inactivation, and, under anaerobic conditions, as a result of irreversible inactivation. However, tyrosine protects the enzyme from being inactivated by dopa under anaerobic conditions. This paper describes how under aerobic conditions the enzyme acting on tyrosine is not directly inactivated but undergoes a process of indirect suicide inactivation provoked by reaction with the o-diphenol originated from the evolution of o-dopaquinone and accumulated in the reaction medium.

3

Stimulatory effect of methyl jasmonate on polyphenol oxidase and peroxidase activities, and starch degradation in scales of tulip bulbs

100%

Saniewski M., Czapski J.

Bulletin of the Polish Academy of Sciences. Biological Sciences

|

1989

|

tom 37

|

nr 1-3

4

Polyphenol oxidase from wheat bran is a serpin

100%

Yamasaki Y., Konno H., Noda K.

Acta Biochimica Polonica

|

2008

|

tom 55

|

nr 2

325-328

Polyphenol oxidase (PPO; EC 1.10.3.2) was isolated from wheat bran by a procedure that included ammonium sulfate fractionation, batch adsorption by DEAE-cellulofine, CM-cellulofine column chromatography, DEAE-cellulofine column chromatography, preparative isoelectric focusing, adsorption on the membrane of a Vivapure Q Maxi H spin column, and heat treatment. These procedures led to 150-fold purification with 4.2% recovery. The PPO was homogeneous by SDS/PAGE. The relative molecular weight of the PPO was estimated to be 37000 based on its mobility in SDS/PAGE. The isoelectric point of the PPO was 4.4. The Kmvalues of the PPO for caffeic acid, chlorogenic acid, pyrocatechol, 4-methyl catechol and l-DOPA as substrates were 0.077, 0.198, 1.176, 1.667 and 4.545 mM. The PPO was strongly inhibited by tropolone. The Kivalue for tropolone is 2.2 × 10–7M. The sequence of the 15 N-terminal amino-acid residues was determined to be ATDVRLSIAHQTRFA, which was identical to those of serpin from Triticum aestivum and protein Z from Hordeum vulgare. The PPO strongly inhibited the activity of trypsin, which is an enzyme of serine proteases; 50% inhibition was observed with 1.5 × 10–7M PPO. The Kivalue for PPO is 2.3 × 10–8M. The wheat bran PPO should be a very important protein for protecting wheat against disease, virus, insect and herbivore damages by both the activities of PPO and protease inhibitor.

5

Polyphenol oxidase and lysozyme mediate induction of systemic resistance in tomato, when a bioelicitor is used

84%

Goel N., Paul P. K.

Journal of Plant Protection Research

|

2015

|

tom 55

|

nr 4

Tomato (Solanum lycopersicum L.) is attacked by Pseudomonas syringae pv. tomato causing heavy damage to the crops. The present study focused on the application of aqueous fruit extracts of neem (Azadirachta indica L.) on a single node of aseptically raised tomato plants. Observations were done, and the changes in the activity and isoenzyme profile of polyphenol oxidase (PPO) and lysozyme, both at the site of treatment as well as away from it, were noted. The results demonstrate that neem extract could significantly induce the activities of both the enzymes as well as upregulate the de novo expression of additional PPO isoenzymes. Induction of systemic acquired resistance (SAR) by natural plant extracts is a potent eco-friendly crop protection method.

6

Purification and characterization of laccase from Pleurotus tuber-regium and its application in dye decolourization

84%

Bamigboye C. O., Oloke J. K., Olaogun B., Alabi Z., Ogunbiyi D., Ogundare A., Akinloye D.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2019

|

tom 100

|

nr 3

7

Silica nanoparticles enhances physio-biochemical characters and postharvest quality of Rosa hybrida L. cut flowers

84%

El-Serafy R. S.

Journal of Horticultural Research

|

2019

|

tom 27

|

nr 1

8

Occurrence and source of hydrogen peroxide in aphids

84%

Urbanska A.

Electronic Journal of Polish Agricultural Universities. Series Biology

|

2009

|

tom 12

|

nr 4

9

Effect of Drechslera graminea on total soluble proteins and defense enzymes of barley

84%

Goel N., Jaiswal G., Srivastava A. K., Paul P. K., Goel A.

Journal of Plant Protection Research

|

2018

|

tom 58

|

nr 3

Barley phylloplane is seriously colonized by Drechslera graminea, the causal agent of leaf stripe disease in the hos. The present study involved the elucidation of alterations induced in the protein content of the host due to Drechslera infection. Naturally growing barley plants were obtained from fields and Drechslera graminea was isolated and identified from diseased plants’ leaves. After identification and preparation of the pure culture, the pathogen was inoculated on plants grown under aseptic and controlled laboratory conditions. Changes in the total soluble cytoplasmic proteins and defense enzymes of the host such as polyphenol oxidase (PPO), peroxidase (POX), phenylalanine lyase (PAL) and tyrosine ammonia lyase (TAL) were observed up to 5 h after inoculation. The results demonstrated a significant effect of the pathogen on the cytoplasmic protein expression of the host as well as in its defense system.

10

The effect of methyl jasmonate on polyphenol oxidase and peroxidase activities in tomato fruit

84%

Czapski J., Saniewski M.

Bulletin of the Polish Academy of Sciences. Biological Sciences

|

1988

|

tom 36

|

nr 4-6

11

Shelf life extension of shrimp (white) using modified atmosphere packaging

84%

Kalleda R. K., Han I. Y., Toler J. E., Chen F., Kim H. J., Dawson P. L.

Polish Journal of Food and Nutrition Sciences

|

2013

|

tom 63

|

nr 2

Wild caught shrimp can have a shortened shelf life compared to farm raised shrimp due to handling and on-ship limitations. The loss of freshness in shrimp is partly due to autolytic reactions caused by endogenous enzymes such as polyphenol oxidase. The objective of this study was to determine the effect of sulfi tes combined with Modified atmosphere packaging (MAP) on the shelf life of non-frozen shrimp. Fresh South Atlantic white shrimp were subjected to one of four treatments, no bisulfite rinse-air packaged, 1.25% bisulfite rinse-air packaged, 1.25% bisulfite rinse-MAP (60% CO2, 18% O2, 22% N2) and 1.25% bisulfite rinse-MAP (36% CO2, 64%N2). The quality and freshness of shrimp was measured by determining total aerobic bacterial populations, package gas headspace analysis, shrimp volatiles (GC-MS), meat pH, nucleotide degradation, and visual analysis. Fresh non-frozen shrimp treated with a combination of sulfites and MAP maintained the shelf life of fresh shrimp up to 10 days while shrimp in non-MAP without sulfite and non-MAP with sulfite developed black spots within 2 and 6 days, respectively. Both MAP treatments slowed bacterial growth while the MAP with high CO2 and with O2 was more effective in preventing off odors and nucleotide degeneration.

12

The mechanism of azide activation of polyphenol oxidase II from tobacco

84%

Shi C., Liu Q., Dai Y., Xie Y., Xu X.

Acta Biochimica Polonica

|

2002

|

tom 49

|

nr 4

So far, azide has been consistently reported to act as an inhibitor of metal enzymes, especially copper proteins. The present work shows that azide can also act as an activator of polyphenol oxidase II (PPO II) from tobacco leaves. From the square-wave voltammetry of native PPO II, peroxide-PPO II complex and azide-PPO II complex, the reduction of nitro blue tetrazolium by the enzymes and activation of PPO II by peroxide it follows that the binding of azide to PPO II induces the formation of CuO2 2-Cu in the active site of PPO II from CuO2 -Cu in native PPO II. The reason for azide acting as an activator can be attributed to azide complexing with PPO II, thus inducing the formation of CuO2 2-Cu, which is the active site of the peroxide-PPO II complex in which peroxide plays the role of activator.

13

Antioxidant defence in maize cultivars triggered by the two-spotted spider mite attack and soil drought – a comparative study

67%

Czapla A., Grudkowska M., Miazek A., Zagdanska B., Kielkiewicz M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2013

|

tom 94

|

nr 2

14

Effect of phenolics from woody plants on activity of grain aphid oxidases

67%

Chrzanowski G., Leszczynski B., Sempruch C., Sytykiewicz H., Sprawka I.

Pestycydy

|

2009

|

nr 1-4

63-70

Changes in activity of the grain aphid peroxidase (Px) and polyphenol oxidase (PPO) towards phenolics isolated from leaves of black currant, sour cherry and walnut were examined. Slight increase in activity of peroxidase was found within insect tissues after 24 h of walnut extract treatment, whereas black currant and sour cherry strongly inhibited activity of this enzyme. Later on, the walnut extract reduced activity of the enzyme, finally about 30%. The other extracts showed slight changes in Px activity. The grain aphid’s polyphenol oxidase was stimulated during the first 24 h of the experiment. Further treatment with the phenolics extracts reduced activity of the grain aphid polyphenol oxidase. Generally, phenolics isolated from the black currant and sour cherry were more effective in reducing activity of the aphid peroxidase, whereas phenolics from walnut reduced the polyphenol oxidase activity. Possible application of the phenolics isolated from the woody plants as modern biopesticides towards the grain aphid is discussed.

15

The biological activities of troponoids and their use in agriculture. A review

67%

Saniewski M., Horbowicz M., Kanlayanarat S.

Journal of Horticultural Research

|

2014

|

tom 22

|

nr 1

16

Substrate specifity and inhibitors of polyphenol oxidase in aspect of darkening of fresh and frozen mushrooms [Agaricus bisporus [Lange] Sing.]

67%

Czapski J.

Acta Agrobotanica

|

1994

|

tom 47

|

nr 1

103-110

Activity of mushroom polyphenol oxidase (PPO) toward 6 substrates and inhibitory effect of cysteine, 2-mercaptoethanol, benzoic acid and sodium metabisulphite were determined. The o-diphenols which appeared to be the best substrates were: catechin, DOPA (L-3,4-dihydroxyphenylalanine) and chlorogenic acid. Affinity of PPO crude preparation substrates to enzyme, expressed as inverse value of Michaelis constant was lower then affinity of catechol. Inhibitory effect depended on specifity of inhibitors and their concentration. Electrophoretic patterns of PPO of mushrooms reveals slow and fast moving 4 isoforms when DOPA was used as a substrate, 2 bands for catechin and chlorogenic acid while only one band showed activity toward tyrosine and p-cresol.

17

Research on catecholases, laccases and cresolases in plants. Recent progress and future needs.

67%

Aniszewski T., Lieberei R., Gulewicz K.

Acta Biologica Cracoviensia. Series Botanica

|

2008

|

tom 50

|

nr 1

Polyphenol oxidases (PPOs) reveal a range of forms and occur in all plants and crops. PPOs are comprised of three enzymes (catecholase, laccase, cresolase) with very different activities and specificities. Cresolase has a dualistic form (cresolase is only in plants and tyrosinase is only in animals and microorganisms). Very often in the literature the generic word "PPO" is used inappropriately as one enzyme. This should be avoided in future studies, as clear systematics and correct nomenclature of PPOs are needed for proper research. PPOs have different substrate specificities and typical inhibitors, and they catalyze hydroxylation and oxidation processes in plants. Pigment formation in cells and cellular systems is affected by active PPOs. Catecholases, laccases and cresolases are encoded by nuclear genes of plants. Various PPO DNA sequences have been found, and PPOs occur in multiple gene families. The protective potential of PPOs in plants and enhanced herbivory resistance is debated, and the final evidence has not yet appeared. The activity of PPOs in germination is recognized, but its mechanism is still not clear. Seed testa coloration in Arabidopsis thaliana is effected by laccase and not by catecholase. The TT10 gene encoding laccase in the Arabidopsis seed testa has been isolated. Arabidopsis genome analysis led to the identification of 16 other putative laccases and their genes, named AtLAC1 to AtLAC17 according to their position in the genome. Challenging areas of research for the future are seed testa PPOs and their mobilization in endosperm and micropylar regions, and PPOs as a part of the plant defense system and immunity.

18

Znaczenie białek w mechanizmach obronnych roślin przed szkodnikami

51%

Kielkiewicz M., Godzina M., Czapla A.

Progress in Plant Protection

|

2010

|

tom 50

|

nr 2

The review focuses on the role of two groups of proteins (anti-nutritive and toxic) in plant defence against insect herbivores.

Ograniczanie wyników

Kinetics properties of polyphenol oxidase in hawthorn (Crataegus spp.)

Indirect inactivation of tyrosinase in its action on tyrosine

Stimulatory effect of methyl jasmonate on polyphenol oxidase and peroxidase activities, and starch degradation in scales of tulip bulbs

Polyphenol oxidase from wheat bran is a serpin

Polyphenol oxidase and lysozyme mediate induction of systemic resistance in tomato, when a bioelicitor is used

Purification and characterization of laccase from Pleurotus tuber-regium and its application in dye decolourization

Silica nanoparticles enhances physio-biochemical characters and postharvest quality of Rosa hybrida L. cut flowers

Occurrence and source of hydrogen peroxide in aphids

Effect of Drechslera graminea on total soluble proteins and defense enzymes of barley

The effect of methyl jasmonate on polyphenol oxidase and peroxidase activities in tomato fruit

Shelf life extension of shrimp (white) using modified atmosphere packaging

The mechanism of azide activation of polyphenol oxidase II from tobacco

Antioxidant defence in maize cultivars triggered by the two-spotted spider mite attack and soil drought – a comparative study

Effect of phenolics from woody plants on activity of grain aphid oxidases

The biological activities of troponoids and their use in agriculture. A review

Substrate specifity and inhibitors of polyphenol oxidase in aspect of darkening of fresh and frozen mushrooms [Agaricus bisporus [Lange] Sing.]

Research on catecholases, laccases and cresolases in plants. Recent progress and future needs.

Znaczenie białek w mechanizmach obronnych roślin przed szkodnikami