Effect of pH on Fenton process using estimation of hydroxyl radical with salicylic acid as trapping reagent

Chang, Chen-Yu; Hsieh, Yung-Hsu; Cheng, Kai Yuan; Hsieh, Ling‐Ling; Cheng, Ta-Chih; Yao, K. S.

doi:10.2166/wst.2008.429

Cited by 64 publications

(36 citation statements)

References 19 publications

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“…2,5-DHBA and 2,3-DHBA were suggested previously to be synthesized by a nonenzymatic reaction in which SA scavenged hydroxyl radicals (Maskos et al, 1990;Chang et al, 2008). The glycosides of 2,5-DHBA and 2,3-DHBA were distributed abundantly in Arabidopsis and were suggested to be formed predominantly from the substrate SA via the IC pathway (Bartsch et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

et al. 2017

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The phytohormone salicylic acid (SA) plays essential roles in biotic and abiotic responses, plant development, and leaf senescence. 2,5-Dihydroxybenzoic acid (2,5-DHBA or gentisic acid) is one of the most commonly occurring aromatic acids in green plants and is assumed to be generated from SA, but the enzymes involved in its production remain obscure. DMR6 (Downy Mildew Resistant6; At5g24530) has been proven essential in plant immunity of Arabidopsis (Arabidopsis thaliana), but its biochemical properties are not well understood. Here, we report the discovery and functional characterization of DMR6 as a salicylic acid 5-hydroxylase (S5H) that catalyzes the formation of 2,5-DHBA by hydroxylating SA at the C5 position of its phenyl ring in Arabidopsis. S5H/DMR6 specifically converts SA to 2,5-DHBA in vitro and displays higher catalytic efficiency (K cat /K m = 4. ) for SA. Interestingly, S5H/DMR6 displays a substrate inhibition property that may enable automatic control of its enzyme activities. The s5h mutant and s5hs3h double mutant overaccumulate SA and display phenotypes such as a smaller growth size, early senescence, and a loss of susceptibility to Pseudomonas syringae pv tomato DC3000. S5H/DMR6 is sensitively induced by SA/pathogen treatment and is expressed widely from young seedlings to senescing plants, whereas S3H is more specifically expressed at the mature and senescing stages. Collectively, our results disclose the identity of the enzyme required for 2,5-DHBA formation and reveal a mechanism by which plants fine-tune SA homeostasis by mediating SA 5-hydroxylation.

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Section: Discussionmentioning

confidence: 99%

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

et al. 2017

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“…Previous studies have shown that SA can scavenge hydroxyl radicals (•OH), resulting in the non-enzymatic formation of both 2,3-and 2,5-DHBA in vitro, with the ratio of these products dependent upon iron ion concentrations and pH (Maskos et al, 1990;Chang et al, 2008). Although highly localized, non-enzymatic production of these compounds could occur during the activation of defences, Bartsch et al (2010) argue that they are predominantly formed enzymatically as i) the levels of total (free plus sugar conjugated) 2,3-DHBA and 2,5-DHBA were not necessarily comparable in Arabidopsis of different ages or mutant backgrounds, and ii) mutations in the Arabidopsis rboh genes, which impact pathogeninducible ROS generation and therefore would be expected to alter non-enzymatic 2,3-and 2,5-DHBA formation, did not affect total 2,3-DHBA accumulation (2,5-DHBA was not analyzed).…”

Section: Conversion To Dihydroxybenzoatesmentioning

confidence: 99%

Salicylic Acid Biosynthesis and Metabolism

Dempsey

Vlot

Wildermuth

et al. 2011

The Arabidopsis Book

628

549

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Salicylic acid (SA) has been shown to regulate various aspects of growth and development; it also serves as a critical signal for activating disease resistance in Arabidopsis thaliana and other plant species. This review surveys the mechanisms involved in the biosynthesis and metabolism of this critical plant hormone. While a complete biosynthetic route has yet to be established, stressed Arabidopsis appear to synthesize SA primarily via an isochorismate-utilizing pathway in the chloroplast. A distinct pathway utilizing phenylalanine as the substrate also may contribute to SA accumulation, although to a much lesser extent. Once synthesized, free SA levels can be regulated by a variety of chemical modifications. Many of these modifications inactivate SA; however, some confer novel properties that may aid in long distance SA transport or the activation of stress responses complementary to those induced by free SA. In addition, a number of factors that directly or indirectly regulate the expression of SA biosynthetic genes or that influence the rate of SA catabolism have been identified. An integrated model, encompassing current knowledge of SA metabolism in Arabidopsis, as well as the influence other plant hormones exert on SA metabolism, is presented.

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“…Previous studies have shown that an acidic pH level near 3 is usually optimum for Fenton’s oxidation processes (Zepp 1992; Ndjou’ou and Cassidy 2006; Papadopoulos et al. 2007; Chang et al. 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have shown that an acidic pH level near 3 is usually optimum for Fenton's oxidation processes (Zepp 1992;Ndjou'ou and Cassidy 2006;Papadopoulos et al 2007;Chang et al 2008). The main features of the Fenton system are said to be based on reagent conditions, thus, [Fe 2+ ], [Fe 3+ ], [H 2 O 2 ] and the reaction characteristics (pH, temperature and the amount of organic and inorganic constituents) (Yoon et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial activities of hydrogen peroxide and its activation by a novel heterogeneous Fenton’s-like modified PAN catalyst

Boateng

Price

Huddersman

et al. 2011

Journal of Applied Microbiology

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Aims: To investigate the potential activation of hydrogen peroxide by a novel catalyst, reducing the concentration of hydrogen peroxide required and the time taken for microbial inactivation. Methods and Results: The antimicrobial properties of an iron‐based novel heterogeneous polyacrylonitrile catalyst in combination with hydrogen peroxide were examined against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus using a modified version of the European suspension test. Antimicrobial activity against Bacillus cereus and Bacillus subtilis endospores was also investigated. Bactericidal activity was significantly increased when the polyacrylonitrile catalyst was combined with hydrogen peroxide. 0·2, 0·5 and 1% w/v hydrogen peroxide resulted in average log reductions of 4·76, 5·59 and 5·37 for E. coli, Ps. aeruginosa and Staph. aureus, respectively, after 60 min exposure at room temperature. The catalyst also significantly increased the activity of hydrogen peroxide against B. subtilis and B. cereus endospores. Conclusions: These studies have demonstrated the potential biocidal use of the novel polyacrylonitrile catalyst when combined with hydrogen peroxide. Significance and Impact of the Study: This is the first publication to demonstrate the enhanced activity gained using the novel heterogeneous catalyst to potentiate the activity of hydrogen peroxide as a biocide.

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Effect of pH on Fenton process using estimation of hydroxyl radical with salicylic acid as trapping reagent

Cited by 64 publications

References 19 publications

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

Salicylic Acid Biosynthesis and Metabolism

Antimicrobial activities of hydrogen peroxide and its activation by a novel heterogeneous Fenton’s-like modified PAN catalyst

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