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Doklady. Biochemistry and Biophysics Nov 2021Plasminogen is a zymogenic form of plasmin, an enzyme that plays a fundamental role in the dissolution of fibrin clots as well as in many other physiological processes....
Plasminogen is a zymogenic form of plasmin, an enzyme that plays a fundamental role in the dissolution of fibrin clots as well as in many other physiological processes. For the first time, by the method of gas chromatography-mass spectrometry, post-translational modifications in the primary structure of plasminogen treated with physiologically relevant amounts of hydrogen peroxide were identified. It was found that methionine and tryptophan residues located in different structural regions of plasminogen served as targets of the oxidant. Plasminogen oxidation caused a dose-dependent effect in decreasing the fibrinogenolytic activity of plasmin evidenced by the formation of fibrinogen degradation products. The possible antioxidant role of methionines in the oxidative modification of plasminogen is discussed.
Topics: Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Oxidants; Peroxides; Plasminogen
PubMed: 34966964
DOI: 10.1134/S1607672921060053 -
Chemosphere Feb 2016This research project investigated the sodium hypochlorite (NaClO) oxidation of aliphatic petroleum contaminants (C10-C50) in a calcareous soil (average 5473 ppm...
This research project investigated the sodium hypochlorite (NaClO) oxidation of aliphatic petroleum contaminants (C10-C50) in a calcareous soil (average 5473 ppm C10-C50, 15 wt% Ca), which had been excavated from a contaminated industrial site. The decontamination objective was to lower the C10-C50 concentration to 700 ppm. CO2 acidity was used in the project to boost the NaClO oxidation yield and seems to have played a role in desorbing the natural organic matter. The experimental conditions were a 2- to 16-h reaction time, at room temperature, with a 1 to 12.5 wt% NaClO oxidative solution and a fixed 2:1 solution-to-soil ratio. With a 3 wt% NaClO solution and with a CO2 overhead, the NaClO dosage requirement was maintained below 60 g NaClO/g of oxidized C10-C50 over the entire decontamination range. The strong chlorine smell remaining after the reaction was completed suggests that part of the NaClO requirement can be recycled. Except traces of chloroform, there were no regulation-listed organochloride contaminants detected on either the treated soil samples or leachates and the total count of chlorinated compounds in treated soil samples was below the detection limit of 250 mg/kg. The NaClO oxidation mechanism on aliphatic substrates might be triggered by transition metals, such as manganese, but no attempt has been made to investigate the oxidation mechanism. Further investigations would include a constant-fed NaClO system and other techniques to lower the required NaClO dosage.
Topics: Environmental Restoration and Remediation; Oxidants; Oxidation-Reduction; Petroleum; Sodium Hypochlorite; Soil; Soil Pollutants
PubMed: 26702553
DOI: 10.1016/j.chemosphere.2015.11.040 -
Biological Signals and Receptors 2001Peroxynitrite anion (ONOO(-)) is a potent biological oxidant produced by the near diffusion-limited reaction of superoxide and nitric oxide. Peroxynitrite has been... (Review)
Review
Peroxynitrite anion (ONOO(-)) is a potent biological oxidant produced by the near diffusion-limited reaction of superoxide and nitric oxide. Peroxynitrite has been implicated in diverse forms of free radical-induced tissue injury. Experimental evidence showed that exogenous and endogenous peroxynitrite causes alterations of the structure and function of mitochondrial proteins, leading to mitochondrial dysfunction and cellular or organ injury. These data are discussed along with its physiopathological implications.
Topics: Energy Metabolism; Mitochondria; Nitrates; Nitric Oxide; Oxidants; Oxidative Stress; Oxygen Consumption
PubMed: 11223641
DOI: 10.1159/000046876 -
Environmental Science & Technology Jan 2016Sulfate radical (SO4(•-)) is a strong, short-lived oxidant that is produced when persulfate (S2O8(2-)) reacts with transition metal oxides during in situ chemical...
Sulfate radical (SO4(•-)) is a strong, short-lived oxidant that is produced when persulfate (S2O8(2-)) reacts with transition metal oxides during in situ chemical oxidation (ISCO) of contaminated groundwater. Although engineers are aware of the ability of transition metal oxides to activate persulfate, the operation of ISCO remediation systems is hampered by an inadequate understanding of the factors that control SO4(•-) production and the overall efficiency of the process. To address these shortcomings, we assessed the stoichiometric efficiency and products of transition metal-catalyzed persulfate oxidation of benzene with pure iron- and manganese-containing minerals, clays, and aquifer solids. For most metal-containing solids, the stoichiometric efficiency, as determined by the loss of benzene relative to the loss of persulfate, approached the theoretical maximum. Rates of production of SO4(•-) or hydroxyl radical (HO(•)) generated from radical chain reactions were affected by the concentration of benzene, with rates of S2O8(2-) decomposition increasing as the benzene concentration increased. Under conditions selected to minimize the loss of initial transformation products through reaction with radicals, the production of phenol only accounted for 30%-60% of the benzene lost in the presence of O2. The remaining products included a ring-cleavage product that appeared to contain an α,β-unsaturated aldehyde functional group. In the absence of O2, the concentration of the ring-cleavage product increased relative to phenol. The formation of the ring-cleavage product warrants further studies of its toxicity and persistence in the subsurface.
Topics: Benzene; Ferric Compounds; Groundwater; Hydroxyl Radical; Manganese Compounds; Minerals; Oxidants; Oxidation-Reduction; Oxides; Phenols; Sulfates; Water Pollutants, Chemical
PubMed: 26687229
DOI: 10.1021/acs.est.5b04815 -
The Journal of Biological Chemistry Sep 2013Peroxynitrite is the product of the diffusion-controlled reaction of nitric oxide and superoxide radicals. Peroxynitrite, a reactive short-lived peroxide with a pKa of... (Review)
Review
Peroxynitrite is the product of the diffusion-controlled reaction of nitric oxide and superoxide radicals. Peroxynitrite, a reactive short-lived peroxide with a pKa of 6.8, is a good oxidant and nucleophile. It also yields secondary free radical intermediates such as nitrogen dioxide and carbonate radicals. Much of nitric oxide- and superoxide-dependent cytotoxicity resides on peroxynitrite, which affects mitochondrial function and triggers cell death via oxidation and nitration reactions. Peroxynitrite is an endogenous toxicant but is also a cytotoxic effector against invading pathogens. The biological chemistry of peroxynitrite is modulated by endogenous antioxidant mechanisms and neutralized by synthetic compounds with peroxynitrite-scavenging capacity.
Topics: Animals; Humans; Hydrogen-Ion Concentration; Mitochondria; Nitric Oxide; Nitrogen; Oxidants; Oxidation-Reduction; Peroxynitrous Acid; Superoxide Dismutase; Superoxides; Tyrosine
PubMed: 23861390
DOI: 10.1074/jbc.R113.472936 -
Journal of Agricultural and Food... Feb 2011Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and...
Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and caseins were oxidized under well controlled conditions at pH 8 as a function of the sanitizing concentration. Different markers for protein oxidation were monitored. The results established that the protein carbonyl content was a rather unspecific marker for protein oxidation, which did not allow one to differentiate the oxidant used especially at the lower concentrations. Cysteine, tryptophan, and methionine were proven to be the most vulnerable amino acids for degradation upon hypochlorous and peracetic acid treatment, while tyrosine was only prone to degradation in the presence of hypochlorous acid. Hypochlorous acid induced oxidation gave rise to protein aggregation, while during peracetic acid induced oxidation, no high molecular weight aggregates were observed. Protein aggregation upon hypochlorous acid oxidation could primarily be linked to tryptophan and tyrosine degradation.
Topics: Amino Acids; Caseins; Disinfectants; Hydrogen-Ion Concentration; Hypochlorous Acid; Milk Proteins; Oxidants; Oxidation-Reduction; Peracetic Acid; Whey Proteins
PubMed: 21214246
DOI: 10.1021/jf1037807 -
Environmental Science and Pollution... Jan 2020In situ chemical oxidations are known to remediate PAH contaminations in groundwater and soils. In this study, batch-scale oxidations aim to compare the PAC (polycyclic...
Ferrate oxidation of polycyclic aromatic compounds (PAHs and polar PACs) on DNAPL-spiked sand: degradation efficiency and oxygenated by-product formation compared to conventional oxidants.
In situ chemical oxidations are known to remediate PAH contaminations in groundwater and soils. In this study, batch-scale oxidations aim to compare the PAC (polycyclic aromatic compound) degradation of three oxidation processes traditionally applied for soil treatment: permanganate, heat-activated persulfate (60 °C) and Fenton-like activated by magnetite, to results obtained with ferrates (Fe). Widely studied for water treatments, ferrates are efficient on a wide range of pollutants with the advantage of producing nontoxic ferric sludge after reaction. However, fewer works focus on their action on soil, especially on semi-industrial grade ferrates (compatible with field application). Oxidations were carried out on sand spiked with dense non-aqueous phase liquid (DNAPL) sampled in the groundwater of a former coking plant. Conventional 16 US-EPA PAHs and polar PACs were monitored, especially potential oxygenated by-products that can be more harmful than parent-PAHs. After seven reaction days, only the Fenton-like showed limited degradation. Highest efficiencies were obtained for heat-activated persulfate with no O-PAC ketones formed. Permanganate gave important degradation, but ketones were generated in large amount. The tested ferrates not only gave slightly lower yields due to their auto-decomposition but also induced O-PAC ketone production, suggesting a reactional pathway dominated by oxidoreductive electron transfer, rather than a radical one.
Topics: Coke; Ferrosoferric Oxide; Groundwater; Iron; Manganese Compounds; Models, Chemical; Oxidants; Oxidation-Reduction; Oxides; Oxygen; Polycyclic Aromatic Hydrocarbons; Polycyclic Compounds; Sand; Soil; Soil Pollutants
PubMed: 31808080
DOI: 10.1007/s11356-019-06841-0 -
The Nature of Resistance of the Coagulation Factor XIII Structure to Hypochlorite-Induced Oxidation.Doklady. Biochemistry and Biophysics Nov 2020The damage to blood coagulation factor XIII (FXIII) at different stages of its enzymatic activation under the action of various physiological amounts of hypochlorite ion...
The damage to blood coagulation factor XIII (FXIII) at different stages of its enzymatic activation under the action of various physiological amounts of hypochlorite ion was studied. The results obtained by HPLC-MS/MS, SDS-PAGE, and colorimetry showed that, during the conversion of FXIII to FXIIIa, the vulnerability of FXIII to hypochlorite-induced oxidation increased. FXIII oxidized with 150 μM hypochlorite completely retained its enzymatic activity inherent to the intact protein, whereas FXIIIa treated with 50 μM hypochlorite showed sharply reduced enzymatic activity. It was shown that a number of methionine and cysteine residues on the catalytic subunit can perform antioxidant function; additionally, the regulatory subunits of FXIII-B contribute to the antioxidant protection of the catalytic center of the FXIII-A subunit, which, together with the tight packing of the tetrameric structure of the FXIII proenzyme, are the three factors that provide high protein resistance to the oxidizing agent.
Topics: Catalytic Domain; Enzyme Activation; Factor XIII; Humans; Hypochlorous Acid; Oxidants; Oxidation-Reduction; Tandem Mass Spectrometry
PubMed: 33368034
DOI: 10.1134/S1607672920050117 -
ACS Nano Jul 2022Whitening agents, such as hydrogen peroxide and carbamide peroxide, are currently used in clinical applications for dental esthetic and dental care. However, the free... (Review)
Review
Whitening agents, such as hydrogen peroxide and carbamide peroxide, are currently used in clinical applications for dental esthetic and dental care. However, the free radicals generated by whitening agents cause pathological damage; therefore, their safety issues remain controversial. Furthermore, whitening agents are known to be unstable and short-lived. Since 2001, nanoparticles (NPs) have been researched for use in tooth whitening. Importantly, nanoparticles not only function as abrasives but also release reactive oxygen species and help remineralization. This review outlines the historical development of several NPs based on their whitening effects and side effects. NPs can be categorized into metals or metal oxides, ceramic particles, graphene oxide, and piezoelectric particles. Moreover, the status quo and future prospects are discussed, and recent progress in the development of NPs and their applications in various fields requiring tooth whitening is examined. This review promotes the research and development of next-generation NPs for use in tooth whitening.
Topics: Tooth Bleaching Agents; Peroxides; Urea; Hydrogen Peroxide; Bleaching Agents; Nanoparticles
PubMed: 35704786
DOI: 10.1021/acsnano.2c01412 -
Food Chemistry Apr 2017During oxidation, the hydroxyl groups of starch molecules are first oxidized to carbonyl groups, then to carboxyl groups. The contents of the carbonyl and carboxyl... (Review)
Review
During oxidation, the hydroxyl groups of starch molecules are first oxidized to carbonyl groups, then to carboxyl groups. The contents of the carbonyl and carboxyl groups in a starch molecule therefore indicate the extent of starch oxidation. The mechanisms of starch oxidation with different oxidizing agents, including sodium hypochlorite, hydrogen peroxide, ozone and sodium periodate, are described in this review. The effects of these oxidizing agents on the molecular, physicochemical, thermal, pasting and morphological properties of starch are described as well. In addition, the main industrial applications of oxidized starches are presented. The present review is important for understanding the effects of oxidation on starch properties, and this information may facilitate the development of novel oxidized starches for both food and non-food applications.
Topics: Hydrogen Peroxide; Molecular Structure; Oxidants; Oxidation-Reduction; Ozone; Periodic Acid; Sodium Hypochlorite; Starch
PubMed: 27979128
DOI: 10.1016/j.foodchem.2016.10.138