Fruit Peroxidase Research Articles

Ascorbate peroxidase in fruits and modulation of its activity by reactive species.

Ascorbate peroxidase (APX) is one of the enzymes of the ascorbate-glutathione cycle and is the key enzyme that breaks down H2O2 with the aid of ascorbate as an electron source. APX is present in all photosynthetic eukaryotes from algae to higher plants and, at the cellular level, it is localized in all subcellular compartments where H2O2 is generated, including the apoplast, cytosol, plastids, mitochondria, and peroxisomes, either in soluble form or attached to the organelle membranes. APX activity can be modulated by various post-translational modifications including tyrosine nitration, S-nitrosation, persulfidation, and S-sulfenylation. This allows the connection of H2O2 metabolism with other relevant signaling molecules such as NO and H2S, thus building a complex coordination system. In both climacteric and non-climacteric fruits, APX plays a key role during the ripening process and during post-harvest, since it participates in the regulation of both H2O2 and ascorbate levels affecting fruit quality. Currently, the exogenous application of molecules such as NO, H2S, H2O2, and, more recently, melatonin is seen as a new alternative to maintain and extend the shelf life and quality of fruits because they can modulate APX activity as well as other antioxidant systems. Therefore, these molecules are being considered as new biotechnological tools to improve crop quality in the horticultural industry.

Carbon dots derived from expired drugs based ratiometric fluorescent sensor for horseradish peroxidase in fruits and vegetables and screening inhibitors.

Household storage of pharmaceuticals to extract raw materials synthesized from carbon points facilitates the utilization of solid waste resources. A novel ratiometric fluorescence sensing technique was developed to ascertain the presence of horseradish peroxidase (HRP) in fruits and vegetables. The method employed a fluorescent probe, synthesized from expired amoxicillin (referred to as carbon dots, or A-CDs), serving as a reference fluorophore. Additionally, 2,3-diaminophenazine (DAP) was utilized as a specific response signal. DAP resulted from a catalytic reaction system involving phenylenediamine and hydrogen peroxide under the catalysis of HRP. The fluorescence intensity corresponding to DAP at 562 nm exhibited a substantial increase, simultaneous with the fluorescence quenching of A-CDs at 450 nm. The ratiometric fluorescence nanosensors displayed a broad linear range and high sensitivity for the detection of HRP. Across the concentration range 0.01 to 6 U L-1, the fluorescence intensity ratio between DAP and A-CDs demonstrated a proportional increase with rising HRP concentration, achieving an impressive detection limit of 0.002 U L-1. The recovery of HRP in fruit and vegetable samples ranged from 96.1 to 103%, with an RSD value of less than 3.8%. Theproposed method facilitated the screening of inhibitors of HRP enzyme activity, contributing to the preservation of freshness in fruits and vegetables.

Effect of Pyroligneous Acid on the Productivity and Nutritional Quality of Greenhouse Tomato.

Pyroligneous acid (PA) is a reddish-brown liquid obtained through the condensation of smoke formed during biochar production. PA contains bioactive compounds that can be utilized in agriculture to improve plant productivity and quality of edible parts. In this study, we investigated the biostimulatory effect of varying concentrations of PA (i.e., 0%, 0.25%, 0.5%, 1%, and 2% PA/ddH2O (v/v)) application on tomato (Solanum lycopersicum ‘Scotia’) plant growth and fruit quality under greenhouse conditions. Plants treated with 0.25% PA exhibited a significantly (p < 0.001) higher sub-stomatal CO2 concentration and a comparable leaf transpiration rate and stomatal conductance. The total number of fruits was significantly (p < 0.005) increased by approximately 65.6% and 34.4% following the application of 0.5% and 0.25% PA, respectively, compared to the control. The 0.5% PA enhanced the total weight of fruits by approximately 25.5%, while the 0.25% PA increased the elemental composition of the fruits. However, the highest PA concentration of 2% significantly (p > 0.05) reduced plant growth and yield, but significantly (p < 0.001) enhanced tomato fruit juice Brix, electrical conductivity, total dissolved solids, and titratable acidity. Additionally, total phenolic and flavonoid contents were significantly (p < 0.001) increased by the 2% PA. However, the highest carotenoid content was obtained with the 0.5% and 1% PA treatments. Additionally, PA treatment of the tomato plants resulted in a significantly (p < 0.001) high total ascorbate content, but reduced fruit peroxidase activity compared to the control. These indicate that PA can potentially be used as a biostimulant for a higher yield and nutritional quality of tomato.

Response surface optimization of the effect of natural essential oils from clove, cumin and fennel in golden delicious apple fruit peroxidase inactivation

Response surface optimization of the effect of natural essential oils from clove, cumin and fennel in golden delicious apple fruit peroxidase inactivation

Gibberellic Acid Induced Changes on Growth, Yield, Superoxide Dismutase, Catalase and Peroxidase in Fruits of Bitter Gourd (Momordica charantia L.)

Bitter gourd is one of the important cucurbits and highly liked among both farmers and consumers due to its high net return and nutritional value. However, being monoecious, it exhibits substantial variation in flower bearing pattern. Plant growth regulators (PGRs) are known to influence crop phenology while gibberellic acid (GA3) is one of the most prominent PGRs that influence cucurbits phenology. Therefore, a field trial was conducted at University of Agriculture Faisalabad to evaluate the impact of a commercial product of gibberellic acid (GA3) on growth, yield and quality attributes of two bitter gourd (Momordica charantiaL.) cultivars. We used five different concentrations (0.4 g, 0.6 g, 0.8 g, 1.0 g, and 1.2 g per litre) of commercial GA3 product (Gibberex, 10% Gibberellic acid). Results showed that a higher concentration of gibberex (1.0 and 1.20 g L−1 water) enhanced the petiole length, intermodal length, and yield of bitter gourd cultivars over control in Golu hybrid and Faisalabad Long. A significant decrease in the enzyme superoxidase dismutase, peroxidase, and catalase activities were observed with an increasing concentration of gibberex (1.0 and 1.20 gL−1 water) as compared to control. These results indicate that the exogenous application of gibberex at a higher concentration (1.2 g L−1) has a dual action in bitter gourd plant: i) it enhances the plant growth and yield, and ii) it also influenced the antioxidant enzyme activities in fruits. These findings may have a meaningful, practical use for farmers involved in agriculture and horticulture.

Redução da severidade da podridão-amarga de maçã em pós-colheita pela imersão de frutos em quitosana

O objetivo deste trabalho foi avaliar a aplicação de quitosana no controle da podridão-amarga da maçã em pós-colheita e seus efeitos sobre Colletotrichum acutatum e a atividade da peroxidase nos frutos. Frutos previamente infectados com o patógeno foram imersos em suspensões de quitosana com diferentes concentrações e pHs. Para estudar possíveis mecanismos de ação envolvidos no controle da doença, foram realizados testes in vitro, para avaliar o efeito da quitosana sobre a germinação de conídios de C. acutatum e sobre o crescimento micelial. Foi avaliada a capacidade da quitosana de induzir a síntese de enzimas relacionadas à defesa da planta (peroxidases), por meio de ensaio espectrofotométrico. Houve efeito de doses e de pH da quitosana sobre a redução da severidade da podridão-amarga em maçã. A suspensão de quitosana a 10 g L-1 e pH 4 foi a mais apropriada tecnicamente para o controle da doença, pois reduziu a severidade em 26%. O polissacarídeo não elevou a atividade de peroxidases nos frutos, mas reduziu a germinação de conídios e o crescimento micelial do patógeno. A quitosana aplicada em pós-colheita é uma medida alternativa aos fungicidas para o manejo da podridão-amarga.

The effect of plant-associative bacteria ( Azospirillum and Pantoea) on the fruit quality of sweet pepper under limited nitrogen supply

This study investigates the influence of a commercial product, Biopron ®, consisting of the bacteria Azospirillum brasilense and Pantoea dispersa on sweet pepper fruits ( Capsicum annuum L.) under limited N supply. When the N supply was reduced from 12 (control) to 7 mmol L −1, the concentration of total-N in the fruits was significantly reduced in both inoculated and non-inoculated plants. The N supply or inoculation did not affect the dry matter content or fruit firmness, but non-inoculated fruit with low N showed a decrease in pericarp thickness and a significant increase in the color parameter a * compared with the control. Under limited N, inoculation increased the concentration of citric, ascorbic and succinic acids in green fruit compared with non-inoculated fruit, which showed lower values than control fruit. At a later (yellow) stage of development, only succinic acid showed a response to inoculation. Fruit peroxidase (EC 1.11.1.7) activity in fruit of inoculated plants was lower than that observed for non-inoculated fruit grown at both high- and low-N. In contrast, in yellow fruit, total phenolic compounds were increased under N limitation, with no inoculation effect. Our study shows that the effect of plant associative bacteria is not directly related with the increased potential availability of nutrients for uptake, especially for fruit quality characteristics.

Partial purification of tomato fruit peroxidase and its effect on the mechanical properties of tomato fruit skin.

Peroxidase (EC 1.11.1.7)-mediated stiffening of cell walls within the fruit skin of tomato is hypothesized to regulate fruit growth. However, to date, there is no experimental evidence demonstrating that peroxidase affects the mechanical properties of skin tissue. Here, the mechanical properties of skin strips excised from a range of fruits at different ages were determined using an 'Instron' universal material testing instrument. The stiffness of tomato fruit skin strips increases 3-fold with increasing fruit age. Application of partially-purified peroxidase from the cell walls of mature tomato fruit skin significantly increased the stiffness of fruit skin irrespective of the age of fruit. Furthermore, the application of hydrogen peroxide significantly increased the stiffness of skin strips excised from fruit of an age when endogenous peroxidase isozymes associated with the termination of growth are first detected. The results support the hypothesis that the tomato fruit skin plays an integral role in the regulation of tomato fruit growth, and that changes in its mechanical properties may be mediated by peroxidase. As far as is known, this is the first demonstration that peroxidases alter the mechanical properties of the plant cell wall.

Purification and Kinetic Characterization of Peroxidase from Tomato Cultivated under Different Salinity Conditions

: By including hydrophobic chromatography in the purification scheme, 2 homogeneous tomato fruit peroxidase isoenzymes were obtained. The expression of these 2 peroxidases, one acid and the other basic, was determined in tomato fruits grown under different salinity conditions. Increased salinity modified the isoenzyme profile of tomato peroxidase. In tomatoes grown under highly saline conditions, there was an increase in the expression of the acid form with respect to the basic, the acid/basic ratio rising from 4.5 in tomatoes grown under normal saline conditions to 70 in those grown in highly saline conditions. Kinetic studies using 2,2′-azinobis(3-ethylbenzo-thiazolinesulfonic acid) as reducing substrate showed that increased salinity in the growth medium did not modify the kinetic parameter of tomato peroxidase over both hydrogen peroxide or reducing substrate.

Peroxidase from Strawberry Fruit (Fragaria ananassa Duch.): Partial Purification and Determination of Some Properties

In this work, peroxidase from strawberry fruit was detected, partially purified, and characterized. The total enzyme extract (both soluble and associated to membranes) was partially purified by means of (NH 4 ) 2 SO 4 precipitation, molecular exclusion chromatography, and cationic exchange chromatography. The purification grade achieved was near 35. Effects of temperature and pH, stability against pH, and thermal stability were analyzed on both crude and partially purified extracts. The maximum enzyme activity was observed at 30 °C and pH 6.0. The enzyme showed low thermal stability and maintained activities equal to or greater than 50% of its maximum value in the 4-11 pH range. Two peroxidase isoenzymes were detected in strawberry fruit ; they were of the basic type (isoelectric points 9.5-10.0) and had molecular masses of 58.1 and 65.5 kDa. Strawberry fruit peroxidase activity decreased remarkably as the fruit ripened and was found primarily in a membrane-bound form. Maximum specific activities were found at the small green and large green ripening stages.

Fractionation and Characterization of Two Forms of Peroxidase fromOryza Sativa

Peroxidase (E.C. 1.11.1.7., hydrogen donor oxidoreductase) is widely distributed and has been isolated from many higher plants (1). The wide distribution of the enzyme suggests that it could be of great biological importance. However the role that it plays in metabolism is not clear due to the large number of reactions it catalyzes and the considerable number of isozymic species (2). In tomato plants, Evans and Aldridge (3) separated out six isoperoxidases and in a later paper Evans reported 12 isoperoxidases from tomato shoots (4). A homogeneous tomato fruit peroxidase isozyme was obtained by Jen et al. (5) using hydrophobic chromatography. Isozymes were not detected in Euphorbia characias peroxidase (6), in Ipomoea batatas peroxidase (7) and in Hordeum vulgare peroxidase (8). The simultaneous presence of Cu (II) amine oxidase and peroxidase in cell walls suggests that the peroxide generated on oxidation of the amines could be utilized by the peroxidase (6,8,9). In the graminea Oryza sativa, widely distributed, an FAD amine oxidase is present that oxidizes diamines (10). In this plant we also found two isoperoxidases called perox I and II. Only perox I was purified to homogeneity and its enzymatic, physical and chemical properties have been studied.

Changes in Soluble and Bound Peroxidase—IAA Oxidase During Tomato Fruit Development

ABSTRACTSoluble peroxidase activity increased dramatically during the early stages of tomato fruit development, reaching a maximum at the mature‐green stage. Ionically and covalently bound peroxidases were also observed, and the activities of these fractions increased steadily throughout fruit development. IAA (indoleacetic acid) oxidase activity was observed in both soluble and bound fractions and paralleled the peroxidase activity. Tissue homogenates from juvenile fruit caused an extended induction period in IAA oxidation reactions catalyzed by the purified tomato fruit peroxidase, suggesting the occurence of a high concentration of phenolic‐type auxin protectors in this tissue. As the fruit developed, tissue homogenates showed a reduction in the amount of auxin protectors as the IAA oxidizing capacity of the fruit increased.

OXIDATION OF INDOLEACETIC ACID BY A HOMOGENEOUS TOMATO FRUIT PEROXIDASE

A purified, homogeneous tomato fruit peroxidase was used to study the oxidation of indoleacetic acid (IAA) in the presence of a phenolic compound and managanese. The reaction was completely inhibited by potassium cyanide and sodium meta-bisulfite when these compounds were added initially. However, when these compounds were added after the reaction had begun, potassium cyanide did not completely inhibit whereas sodium meta-bisulfite did. Also, the ultraviolet spectrum of the reaction products indicated that methyleneoxindole was the primary product. Several monophenols were capable of serving as cofactors, but o-dihydroxyphenols were inhibitors of IAA oxidation by tomato peroxidase. The inhibition was characterized by an extension of the induction period after which oxidation proceeded as normal. These results suggest that IAA oxidation by tomato fruit peroxidase proceeds autocatalytically via a free radical mechanism and that o-dihy-droxyphenols could be serving as chain-stopping agents. The changes in the phenolic pool during fruit development could affect IAA oxidation and be related to the fruit ripening process.

Preparation of a homogeneous tomato fruit peroxidase.

Tomato fruit (Lycopersicon esculentum Mill cv. Walters) peroxidase was purified to apparent homogeneity by a three step procedure: hydrophobic chromatography, DEAE Sephacel chromatography and semi-preparative electrophoresis. A purification of 71 fold and a yield of 52% relative to crude extract were obtained. The pure enzyme was brown in color and showed a molecular weight of 45,000 as estimated from SDS disc gel electrophoresis and gel filtration on Ultrogel AcA 34. The pH optimum of tomato peroxidase varied with substrate dyes used and the enzyme may have some hydrophobic properties near its active site. The optimum temperature was 35 degrees C for this enzyme, and IAA oxidase activity was evident in the presence of 2,4-dichlorophenol and manganese. The apparent KM for IAA was measured to be 0.24 mM.

TOMATO PEROXIDASE: PURIFICATION VIA HYDROPHOBIC CHROMATOGRAPHY

ABSTRACTWith a large number of isoenzyme species and substrates, peroxidases have been difficult to purify to homogeneity. By including hydrophobic chromatography in the purification scheme, a homogeneous tomato fruit peroxidase isoenzyme was obtained. The isoenzyme had a clean spectrum in the visible region and a Rz (403 nm/280 nm) value of 2.36. It showed up as a single band in disc gel electrophoresis in basic and acidic buffers, in acetate strip electrophoresis, and in both tube and slab gel SDS electrophoresis. Molecular weight estimation of this tomato peroxidase was 43,000 ± 2,000 daltons. The pH optima were at 5.5 and 7.5 with guaiacol and pyrogallol as substrate, respectively. Kinetic studies showed that pyrogallol and hydrogen peroxide could provide substrate inhibition at 5 mM concentration. Hydrophobic chromatography may be useful for purification of other food enzymes similar to tomato peroxidase.

THE OXIDASE OF THE APRICOT

The flesh of fresh apricots when cut and exposed to the air rapidly develops a brown color due to enzymic oxidation. This phenomenon is of great importance in the freezing and freezing storage of fresh apricots and in the preparation of apricots for canning and drying. In commercial freezing the oxidizing enzymes of this fruit are controlled by treatment with dilute SO2 solution or by covering the fruit with sirup containing ascorbic acid. In canning the enzymes are destroyed by heat, and in drying they are inhibited by S02. Sumner and Somers (11), Onslow (5) and others have reviewed the early research on the oxidizing enzymes of plant tissue. Therefore, we shall cite only a few papers that bear more or less directly on fruit oxidases and refer the reader to texts such as the above for a more comprehensive review. Samisch (8, 9, and 10) who conducted research on apricot oxidase in this laboratory used a Barcroft manometric apparatus with catechol as the substrate in studying certain properties of this enzyme or enzyme system. He showed that phenolase activity was greatest in the peel and vascular bundles. He investigated the effect of pH value and various enzymes on apricot phenolase, using catechol as the substrate. Potatoes possess a very active oxidase, classified by Boswell and Whiting (1938) as a polyphenolase. Samisch (8) defines polyphenolases as ' ' oxidases which have the power to catalyze the oxidation of phenols or their derivatives by molecular oxygen.'' Peroxidases do not have this power and require the presence of H202. However, Szent-Gy?rgyi (12) suggested that peroxidases are merely attenuated polyphenolases that have lost the power of catalyzing the oxidation of phenols by atmospheric oxygen. Cruess and Fong (2) showed that the inactivation temperature of fruit peroxidase varies with the hydrogen-ion concentration of the medium; that there is an optimum H202 concentration for fruit peroxidases, and that the optimum pH value varies with the oxidase indicator used; i.e., optimum pH appears to be a function of the substrate rather than of the