Showing papers on "Hydrogen peroxide published in 1973"
TL;DR: In the procedure presented here, hydrogen peroxide is measured by reaction with quadrivalent titanium and xylenol orange, which constitutes a one-enzyme assay with stable reagents, which does not require protein precipitation and is not subject to interference from hemoglobin or bilirubin.
Abstract: I describe the characterization, extraction, and purification of a cholesterol:oxygen oxidoreductase (EC 1.1.3.6) from Nocardia sp. This enzyme catalyzes oxidation of cholesterol to Δ4-choIestenone, with production of hydrogen peroxide. It is very stable, active over a wide pH range, and has a Km of 1.4 x 10-5 mol/ liter. It is highly specific for Δ4- or Δ5-3β-hydroxycholestanes, and may be applied to the assay of serum total cholesterol. In the procedure presented here, hydrogen peroxide is measured by reaction with quadrivalent titanium and xylenol orange. This constitutes a one-enzyme assay with stable reagents, which does not require protein precipitation and is not subject to interference from hemoglobin or bilirubin.
1,476 citations
390 citations
TL;DR: A survey of 38 axenic isolates of blue‐green algae indicated that over half the isolates produced hydrogen peroxide under defined growth conditions, and three kinetic profiles for the formation of hydrogenperoxide were observed.
Abstract: SUMMARY
A survey of 38 axenic isolates of blue-green algae indicated that over half the isolates produced hydrogen peroxide under defined growth conditions. Three kinetic profiles for the formation of hydrogen peroxide, were observed; these are described. The possible site or sites of hydrogen peroxide formation remain unknown.
257 citations
Patent•
07 Sep 1973
TL;DR: In this article, the authors describe a process in which air containing a pollutant, such as hydrogen sulfide, sulfur dioxide, or an organic compound such as a mercaptan, an aldehyde, an amine, an alcohol, and the like, is contacted with a liquid impermeable module or cell having as a surface thereof a liquidimpermeable and gas-permeability membrane and containing an agent which reacts with the pollutant to convert it to one or more innocuous substances, whereby the pollutants passes through the membrane and is reacted with the agent,
Abstract: Air containing a pollutant, such as hydrogen sulfide, sulfur dioxide or an organic compound such as a mercaptan, an aldehyde, an amine, an alcohol, and the like, is contacted with a liquid impermeable module or cell having as a surface thereof a liquidimpermeable and gas-permeable membrane and containing an agent which reacts with the pollutant to convert it to one or more innocuous substances, whereby the pollutant passes through the membrane and is reacted with the agent, thus reducing the concentration of the pollutant in the air. The membrane is desirably comprised of an inorganic powder which may serve as an absorbent, preferably powdered activated carbon, dispersed in an inert, hydrophobic polymer such as polytetrafluoroethylene, and the reactive agent is desirably an aqueous solution of an oxidizing agent, preferably hydrogen peroxide. The module is preferably provided with means to regenerate the reactive agent which, in the case of aqueous solutions of oxidizing agents, can be an electrolytic cell in which the spent oxidizing agent is regenerated by electrolytic technique.
241 citations
TL;DR: The sporicidal properties of hydrogen peroxide were evaluated at concentrations of 10 to 41% and at temperatures of 24 to 76 C as discussed by the authors, and the organisms tested and their relative resistance at 24 C to 25.8% H2O2 were: Bacillus subtilis SA 22 > B. subtILis var. globigii, B. stearothermophilus > Clostridium sp. putrefactive anaerobe 3679 > S. aureus, with "D" values of 7.3, 2, 1.8
Abstract: The sporicidal properties of hydrogen peroxide were evaluated at concentrations of 10 to 41% and at temperatures of 24 to 76 C. The organisms tested and their relative resistance at 24 C to 25.8% H2O2 were: Bacillus subtilis SA 22 > B. subtilis var. globigii > B. coagulans > B. stearothermophilus > Clostridium sp. putrefactive anaerobe 3679 > S. aureus, with “D” values of 7.3, 2, 1.8, 1.5, 0.8., and 0.2 min, respectively. Heat shocking spores prior to hydrogen peroxide treatment decreased their resistance. Wet spores were more resistant than dry spores when good mixing was achieved during hydrogen peroxide treatment. Inactivation curves followed first-order kinetics except for a lag period where the inactivation rate was very slow. Increasing the H2O2 concentration and the temperature reduced the lag period.
109 citations
TL;DR: Phenol and its oxidized products are shown to be substrates in the HRP, H2O2 enzyme system and the homogeneous nature of the product of phenol oxidation suggests that the radical generated remains enzyme-bound until coupling occurs.
102 citations
TL;DR: The net rate of formation of H2O2 appears to be independent of concomitant substrate hydroxylation in microsomes from controls and phenobarbital treated animals and its fate might be linked to the spin state of cytochrome P-450.
93 citations
TL;DR: The role of peroxide is discussed in maintaining a balance of the indigenous dental plaque flora and the potential for a bactericidal activity in vivo by Strep.
92 citations
TL;DR: In this article, a detailed development of the methods using ferric-xylenol orange and titanium-oxide orange-hydrogen peroxide complexes for the determination of H2O2 formed in irradiated solutions is presented.
81 citations
Journal Article•
TL;DR: Treatment of rats for 21-28 days with a semiliquid diet containing ethanol resulted in a near doubling of liver microsomal cytochrome P-450 content, and statistically significant increases in the rate of NADPH oxidation, "endogenous" respiration, and acetaldehyde formation from ethanol in microsomes were observed.
Abstract: Treatment of rats for 21-28 days with a semiliquid diet containing ethanol resulted in a near doubling of liver microsomal cytochrome P-450 content. Concomitantly, statistically significant increases in the rate of NADPH oxidation, "endogenous" respiration, and acetaldehyde formation from ethanol in microsomes were observed. An average increase in NADPH-dependent hydrogen peroxide formation of 45 ± 7% (SE) was observed as a result of chronic ethanol treatment, employing the decrease in scopoletin fluorescence or the formation of cytochrome peroxidase complex II as hydrogen peroxide-detecting systems. Since it has been reported that the rate-limiting step for ethanol oxidation in microsomes is the rate of generation of hydrogen peroxide for the peroxidatic reaction of catalase [R. G. Thurman, H. G. Ley, and R. Scholz, Eur. J. Biochem. 25, 420-430 (1972)], this adaptive increase in hydrogen peroxide production due to chronic ethanol treatment most likely accounts for the enhanced ethanol oxidation via catalase-H 2 O 2 . The data are consistent with the hypothesis that microsomal ethanol oxidation is due to peroxidation via catalase utilizing microsomal hydrogen peroxide.
74 citations
TL;DR: On the basis of stoichiometric relation of reactions between IAA and peroxidase peroxide compounds a tentative scheme of P-670 formation during the oxidation of IAA was presented and IAA peroxide radical instead of superoxide anion radical was suggested to be an intermediate in the oxidation.
TL;DR: The rate of the reaction between hydrogen peroxide and cysteine or cysteamine is proportional to [H2O2] and [NH3+CHXCH2S]- consistent with nucleophilic attack by the thiolate ions on peroxide oxygen.
Abstract: The rate of the reaction between hydrogen peroxide and cysteine or cysteamine is proportional to [H2O2] and [NH3+CHXCH2S–](X = H or CO2–) consistent with nucleophilic attack by the thiolate ions on peroxide oxygen. The rate decreases at higher pH where loss of the NH3+ proton occurs, and it is suggested that hydrogen bonding between this group and hydrogen peroxide facilitates the reaction.
TL;DR: The interaction of substrates with a 4-methoxybenzoate O-demethylating enzyme system was studied by use of crude cell-free extracts and by the purified enzyme system, which requires NADH and oxygen as cofactors and acts on various substrates.
Abstract: The interaction of substrates with a 4-methoxybenzoate O-demethylating enzyme system was studied by use of crude cell-free extracts and also by the purified enzyme system. The two components of the enzyme system, an iron-containing flavoprotein and an iron-sulphur protein, were obtained in pure state from Pseudomonas putida grown on 4-methoxybenzoate as the sole carbon source. The purified enzyme system requires NADH and oxygen as cofactors and acts on various substrates. The highest affinity is found for 4-methoxybenzoate, but also N-methyl-4-aminobenzoate is demethylated and 4-alkylbenzoates are hydroxylated at the side chain. The enzyme is rather specific for para-substituted benzoic acid derivatives whereas 3-methoxybenzoate and 4-hydroxy-3-methoxybenzoate are demethylated slowly. The enzyme is also able to hydroxylate the aromatic ring. This is shown by the isolation of 3,4-dihydroxybenzoate as the hydroxylation product of 3-hydroxy- or 4-hydroxy-benzoate, respectively. Studies on substrate binding and oxygen consumption with substrate analogues showed an absolute requirement for the carboxy group at the aromatic ring. Benzoic acid derivatives without a suitable CH-bond uncouple oxygen uptake with a concomitant formation of hydrogen peroxide. Measurements of oxygen consumption indicate that the affinity towards oxygen is substrate dependent, probably due to steric alterations as a consequence of substrate binding.
TL;DR: The kinetics of these reactions indicate stability of the reduced protein toward oxygen and facilitation of reoxidation by anion binding and the results support the same type of mechanism.
TL;DR: The nature of the rate-limiting step was elucidated by studying the effects of alterations in ionic strength, dielectric constant and deuterium substitution on the velocity of the forward reaction.
Abstract: 1. The oxidation of p-dimethylaminomethylbenzylamine was followed spectrophotometrically by measuring the change in E250 caused by the p-dimethylaminomethylbenzaldehyde produced under a wide variety of experimental conditions. 2. The effect of variations in concentrations of both substrates (amine and oxygen) and all products (aminoaldehyde, hydrogen peroxide and ammonia) on this reaction was studied and the results used to develop a formal mechanism. 3. The nature of the rate-limiting step was elucidated by studying the effects of alterations in ionic strength, dielectric constant and deuterium substitution on the velocity of the forward reaction. 4. Thermodynamic activation energy parameters were obtained at several pH values from the effects of temperature on the reaction.
TL;DR: In this article, aqueous alkaline hydrogen peroxide solutions at 0° degrade aldohexoses almost quantitatively to 6 moles of formic acid, and aldopentoses to 5 moles.
TL;DR: Kinetic data indicate that the reaction between enzyme and superoxide anion shows a logarithmic dependence on concentration under the conditions of the method, and identifies great similarity in the molecular properties of the enzyme from eucaryotic organisms.
Abstract: Superoxide dismutase catalyzes the conversion of the single electron reduced species of molecular oxygen to hydrogen peroxide and oxygen. The widely distributed copper enzyme has been purified from two fungi. Identical chromatographic and electrophoretic behavior of the enzyme isolated from different sources indicates great similarity in the molecular properties of the enzyme from eucaryotic organisms. A photosensitized recording assay procedure for the enzyme was developed which elminates the use of a second enzyme system for generating the substrate, superoxide anion. Kinetic data indicate that the reaction between enzyme and superoxide anion shows a logarithmic dependence on concentration under the conditions of the method.The fungal enzyme contains 2 mol of zinc and 2 mol of copper per mole of holoenzyme. The reaction between the enzyme-bound copper and several catechol derivatives has been examined through the use of electron spin resonance spectroscopy. It was concluded from these studies that these...
Patent•
26 Nov 1973
TL;DR: In this article, a method of chemically polishing copper and copper alloys is described, which comprises using a solution with one or more members selected from azoles having the structure represented by the general formulae ##SPC1## wherein X, X' and X" represent any of hydrogen, amino, aminoalkyl and alkyl added to an acid aqueous solution of hydrogen peroxide.
Abstract: This invention provides a method of chemically polishing copper and copper alloys which comprises using a solution with one or more members selected from azoles having the structure represented by the general formulae ##SPC1## Wherein X, X' and X" represent any of hydrogen, amino, aminoalkyl containing 1-3 carbon atoms and alkyl containing 1-3 carbon atoms added to an acid aqueous solution of hydrogen peroxide containing hydrogen peroxide and sulfuric or nitric acid.
Journal Article•
TL;DR: It is concluded that free OH radical, even if it exists, is not liberated into the solution in the methemoglobin-hydrogen peroxide system.
TL;DR: It is shown that although catalase shows little or no effect on the oxidation, superoxide dismutase strongly inhibits the oxidation of Pholad luciferin, luminol and a wide range of other compounds by superoxide ion produced electrolytically or by oxidation of H 2 O 2 with sodium periodate.
TL;DR: Horseradish peroxidase and hydrogen peroxide form phenoxy radicals from 4-substituted-2,6-dimethoxyphenols, milled wood lignin and alkali lignins as mentioned in this paper.
TL;DR: 3-hydroxybenzoate 6-hydroxylase thus resembles other flavoprotein hydroxylases in the general regulatory properties dictated by their aromatic substrates, pseudosubstrates or effectors.
TL;DR: The optical and E P R -~pectra results of this new species and the existence of an intermediate with similar :ovticat properties has been described for cemloplasm~ by Manabe e /~] : I ] O].
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TL;DR: Methyl oleate is converted in high yield to methyl 9(10)-methoxystearate by reaction with methanol in the presence of mercuric acetate followed by demercuration with sodium borohydride as discussed by the authors.
TL;DR: In this article, the free energy of preferential solvation has been determined where ΔG⊖ps=−RT ln K and K is the equilibrium constant for the overall process.
Abstract: Studies of the alkali metal (7Li, 23Na, 87Rb, 133Cs) and halide (19F, 35Cl) resonance chemical shifts have been made in H2O2+ H2O solvent mixtures up to 85 % w/w peroxide with the addition of 10–3 mol kg–1 ethylenediaminetetra-acetic acid (EDTA) to complex transition metal ion impurities. When the chemical shifts were dependent on salt concentration, results were extrapolated to zero salt concentration. The variation of these infinite dilution shifts with peroxide mole fraction shows Rb+, Cs+ and F– to be preferentially solvated by peroxide and Li+ preferentially solvated by water. These conclusions can be put on a quantitative basis by assuming that the solvation changes can be represented by a series of n competitive equilibria, where n is the solvation number, assumed to be the same for both water and peroxide. The free energy of preferential solvation has been determined where ΔG⊖ps=–RT ln K and K is the equilibrium constant for the overall process X(H2O)n+ H2O2⇌ X(H2O2)n+nH2O. K is related to the equilibrium constant for the ith step by K=[iKi/(n+ 1 –i)]n. The relation of ΔG⊖ps to the free energy of transfer of a neutral combination of ions from one solvent to another, ΔG⊖t, is discussed.
TL;DR: The reaction products show that the oxidation takes place almost entirely with cleavage of the C-2C-3 bond of the parent sugar, which suggests a free-radical, rather than a base-catalyzed, mechanism for the oxidative cleaving of the adduct.
TL;DR: In this paper, the Pronase digestibility test was used for the determination of methionine sulfoxide in casein, and the results showed that methionines were released as free methions.
Abstract: Analytical methods were adapted to the determination of methionine sulfoxide and methionine sulfone in casein. Direct determination by alkaline hydrolysis appears to be more accurate than indirect determination by the carboxymethylation-performic oxidation method. Proteolysis of casein with Pronase was adopted as an in vitro digestibility test. In the conditions chosen, 41% of the methionine residues of casein were released as free methionine. A solution of casein was treated with up to 0.12M hydrogen peroxide. No methionine sulfone was formed. Most of the methionine residues were oxidized into methionine sulfoxide. When milk was treated with 0.018M hydrogen peroxide, 51% of its methionine residues was transformed into methionine sulfoxide. Hydrogen peroxide-oxidized casein samples were submitted to the Pronase digestibility test. Release of free methionine was inversely related to the methionine sulfoxide content. No free methionine sulfoxide was released from casein. Release of other amino acids was little affected by hydrogen peroxide treatment. Similar results were found with milk.
TL;DR: Hydrogen peroxide efficiently protects horseradish peroxidase against inactivation by hydroxymethylhydroperoxide, whereas the hydrogen donor substrate guaiacol has little protective effect.