Studies on the autocatalyzed oxidation of amino acids by peroxomonosulfate

Kannan, R. Sayee; Ramachandran, M.

doi:10.1002/kin.10147

Cited by 8 publications

(4 citation statements)

References 9 publications

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“…PMS has also been used as a mild oxidant in organic synthesis in nonaqueous solvents, where it can oxidize alkenes to epoxides, aldehydes to carboxylic acids, phosphines to phosphine oxides, and sulfides to sulfones . In water, it is known to convert amino acids to various products. − …”

Section: Introductionmentioning

confidence: 99%

Oxidation of Organic Compounds in Water by Unactivated Peroxymonosulfate

Yang

Banerjee²,

Brudvig³

et al. 2018

Environ. Sci. Technol.

687

176

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Peroxymonosulfate (HSO and PMS) is an optional bulk oxidant in advanced oxidation processes (AOPs) for treating wastewaters. Normally, PMS is activated by the input of energy or reducing agent to generate sulfate or hydroxyl radicals or both. This study shows that PMS without explicit activation undergoes direct reaction with a variety of compounds, including antibiotics, pharmaceuticals, phenolics, and commonly used singlet-oxygen (O) traps and quenchers, specifically furfuryl alcohol (FFA), azide, and histidine. Reaction time frames varied from minutes to a few hours at pH 9. With the use of a test compound with intermediate reactivity (FFA), electron paramagnetic resonance (EPR) and scavenging experiments ruled out sulfate and hydroxyl radicals. Although O was detected by EPR and is produced stoichiometrically through PMS self-decomposition, O plays only a minor role due to its efficient quenching by water, as confirmed by experiments manipulating the O formation rate (addition of HO) or lifetime (deuterium solvent isotope effect). Direct reactions with PMS are highly pH- and ionic-strength-sensitive and can be accelerated by (bi)carbonate, borate, and pyrophosphate (although not phosphate) via non-radical pathways. The findings indicate that direct reaction with PMS may steer degradation pathways and must be considered in AOPs and other applications. They also signal caution to researchers when choosing buffers as well as O traps and quenchers.

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Section: Introductionmentioning

confidence: 99%

Oxidation of Organic Compounds in Water by Unactivated Peroxymonosulfate

Yang

Banerjee²,

Brudvig³

et al. 2018

Environ. Sci. Technol.

687

176

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“…The transformation of several aliphatic amino acids by PMS has been reported at elevated temperatures (30–45 °C) and low pH values (≤5.2): glycine, alanine, leucine, valine, serine, and threonine. These studies reported rate constants determined by following the concentration of PMS and not the amino acid; the products of reaction were determined by a spot test and found to be aldehydes in all cases. − Oxidation of methionine (Met)- and tryptophan (Trp)-containing peptides by PMS has also been studied, but rate constants were not determined . In the case of methionine, the oxidation product was found to be methionine sulfone; transformation products of Trp were not reported .…”

Section: Introductionmentioning

confidence: 99%

Peroxymonosulfate Oxidizes Amino Acids in Water without Activation

Ruiz

Yang

Lochbaum

et al. 2019

Environ. Sci. Technol.

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A variety of peptidic and proteinaceous contaminants (e.g., proteins, toxins, pathogens) present in the environment may pose risk to human health and wildlife. Peroxymonosulfate is a strong oxidant (E H 0 = 1.82 V for HSO5 –, the predominant species at environmental pH values) that may hold promise for the deactivation of proteinaceous contaminants. Relatively little quantitative information exists on the rates of peroxymonosulfate reactions with free amino acids. Here, we studied the oxidation of 19 of the 20 standard proteinogenic amino acids (all except cysteine) by peroxymonosulfate without explicit activation. Reaction half-lives at pH 7 ranged from milliseconds to hours. Amino acids possessing sulfur-containing, heteroaromatic, or substituted aromatic side chains were the most susceptible to oxidation by peroxymonosulfate, with rates of transformation decreasing in the order methionine > tryptophan > tyrosine > histidine. The rate of tryptophan oxidation did not decrease in the presence of an aquatic natural organic matter. Singlet oxygen resulting from peroxymonosulfate self-decomposition, while detected by electron paramagnetic resonance spectroscopy, was unlikely to be the principal reactive species. Our results demonstrate that peroxymonosulfate is capable of oxidizing 19 amino acids without explicit activation and that solvent-exposed methionine and tryptophan residues are likely initial targets of oxidation in peptides and proteins.

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“…In situ generated oxirane from the PMS/acetone system in alkaline medium is widely used to carry out a variety of synthetically useful oxidation reactions of organic compounds under mild conditions [16][17][18]. The oxidation of alphaamino acids by PMS in acidic pH shows autocatalysis, and the aldehyde intermediate produced during the oxidation catalyzes the reaction [19,20]. Thus, PMS reactions proceed through different intermediates and mechanisms, depending upon the nature of the catalyst and/or substrate.…”

Section: Peroxomonosulfate (Pms) Ion Hsomentioning

confidence: 99%