THE ROLE OF PLANT PHENOLIC COMPOUNDS IN THE OXIDATION OF REDUCED DIPHOSPHOPYRIDINE NUCLEOTIDE BY PEROXIDASE

1961 ◽  
Vol 39 (7) ◽  
pp. 1113-1124 ◽  
Author(s):  
O. L. Gamborg ◽  
L. R. Wetter ◽  
A. C. Neish
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Indoleacetic Acid ◽  
Enzyme System ◽  
Reduced Glutathione ◽  
Maximum Activity ◽  
Coumaric Acid ◽  
Horse Radish Peroxidase ◽  
Competitive Inhibitors

Horse-radish peroxidase and dialyzed extracts from pea epicotyls and from spruce shoots oxidized reduced diphosphopyridine nucleotide in the presence of p-coumaric acid. Maximum activity was obtained when hydrogen peroxide, Mn+2, p-coumaric acid, and enzyme were present. p-Hydroxyphenylpropionic acid, p-hydroxyphenylpyruvic acid, tyrosol, or resorcinol could replace p-coumaric acid as the phenolic activator but they were less efficient. Ferulic and sinapic acids were competitive inhibitors while chlorogenic acid, caffeic acid, and hydroquinone were non-competitive inhibitors of the reaction. The oxidation of the reduced coenzyme was inhibited by citrate and pyrophosphate, enhanced by versene, and delayed by ascorbic acid, cysteine, and reduced glutathione. The results indicate that the peroxidase system may be identical with the enzyme system which oxidizes indoleacetic acid.

scholarly journals Glutathione and ascorbic acid in spinach (Spinacia oleracea) chloroplasts. The effect of hydrogen peroxide and of Paraquat

1983 ◽  
Vol 210 (3) ◽  
pp. 899-903 ◽  
Author(s):  
M Y Law ◽  
S A Charles ◽  
B Halliwell
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Spinacia Oleracea ◽  
Reduced Glutathione ◽  
Oxidized Glutathione ◽  
Fructose Bisphosphatase ◽  
Physiological Conditions ◽  
Spinach Chloroplasts ◽  
Apparent Loss

The stroma of spinach chloroplasts contains ascorbic acid and glutathione at millimolar concentrations. [Reduced glutathione]/[oxidized glutathione] and [ascorbate]/[dehydroascorbate] ratios are high under both light and dark conditions and no evidence for a role of oxidized glutathione or dehydroascorbate in the dark-deactivation of fructose bisphosphatase could be obtained. Addition of H2O2 to chloroplasts in the dark decreases the above ratios, an effect that is reversed on illumination. Addition of Paraquat to illuminated chloroplasts caused a rapid oxidation of reduced glutathione and ascorbate, and apparent loss of dehydroascorbate. Paraquat rapidly inactivated fructose bisphosphatase activity, as assayed under physiological conditions.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

The formation of choleglobin and the role of catalase in the erythrocyte

1949 ◽  
Vol 136 (884) ◽  
pp. 435-448 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Catalase Activity ◽  
Acid Oxidase ◽  
Small Decrease ◽  
Amino Acid Oxidase ◽  
Oxidase System ◽  
Inverse Proportion

In haemolysates of non-nucleated erythrocytes there is an inverse proportion between catalase activity and rate of choleglobin formation on addition of ascorbic acid. In the intact erythrocytes catalase protects haemoglobin against oxidation and further destruction by the hydrogen peroxide generated by the D-amino-acid oxidase system or by physiological concentrations of ascorbic acid and glutathione. Acid destromatization of haemolyzed horse erythrocytes causes a small decrease in the catalase activity and an increased rate of inactivation of the remaining catalase by ascorbic acid. The liberation of copper from haemocuprein is quantitatively insufficient to explain the decreased stability of the catalase. Exposing duck oxyhaemoglobin, but not reduced haemoglobin, to a pH of 5⋅5 to 5⋅8, causes an alteration which is apparent from the increase of the rate of choleglobin formation. The mechanism of this alteration is discussed. It partly explains the 'stroma effect', at least in duck erythrocytes. In addition, in the latter, there is a true stroma effect. Choleglobin formation in the presence of ascorbic acid is accelerated by a variety of substances. Some of these perturb haemoglobin, while others increase the formation of hydrogen peroxide from ascorbic acid. The implications of our findings on the mechanism of choleglobin formation and on the role of catalase in the erythrocyte are discussed.

Involvement of intramural prostaglandin E2 in prenatal patency of the lamb ductus arteriosus

1986 ◽  
Vol 64 (6) ◽  
pp. 737-744 ◽  
Author(s):  
Flavio Coceani ◽  
Dayle Huhtanen ◽  
Nancy C. Hamilton ◽  
Isis Bishai ◽  
Peter M. Olley
Keyword(s):  
Release Rate ◽  
Enzyme System ◽  
Reduced Glutathione ◽  
Ductus Arteriosus ◽  
Prostaglandin E ◽  
Concomitant Treatment ◽  
Contractile State ◽  
Wet Weight ◽  
Near Term

Release of prostaglandin E2 (PGE2) was studied in isolated ductus arteriosus preparations from immature (103 or 104 days gestation; term, 147 days) and near-term fetal lambs. Mature preparations produced measurable amounts of the compound in most cases and the release rate was 19 ± 2 pg/(100 mg wet weight∙min) at a [Formula: see text] of 3–8 Torr (1 Torr = 133.3 Pa). PGE2 release increased with the [Formula: see text] of the medium, peak values (about 125 pg/(100 mg∙min)) being attained at 106–276 Torr when the oxygen-induced contraction was still submaximal. Experiments in which tissues were either contracted with excess potassium or relaxed with CO proved that PGE2 formation is independent from the contractile state. PGE2 was also released from ductus preparations lacking the adventitia, the intima, or both; however, release values were maximal when the adventitia was preserved. The magnitude of the intrinsic tone in these stripped preparations was inversely related to the rate of PGE2 formation. Reduced glutathione increased PGE2 release from the mature ductus, whole or stripped, and also relaxed hypoxic preparations; both effects were reversed by concomitant treatment with indomethacin. PGE2 synthesis tended to be greater in the immature than the mature ductus, maximal values (115 ± 27 pg/(100 mg∙min)) being observed at 6–8 Torr. We conclude that the ductus arteriosus is endowed with an enzyme system for the synthesis of PGE2 whose function accords with an effector role of the compound in the regulation of tone. These findings, together with the potent relaxation exerted by PGE2 at low [Formula: see text], indicate that the locally generated prostaglandin is well suited for keeping the ductus patent in the fetus.

Erythrocyte defenses against hydrogen peroxide: the role of ascorbic acid

1998 ◽  
Vol 1380 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Shalu Mendiratta ◽  
Zhi-chao Qu ◽  
James M May
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid

scholarly journals Oxidative stress and low molecular weight antioxidants in triticale shoots under chloride salinization

2020 ◽  
Vol 62 (6) ◽  
pp. 125-130
Author(s):  
Viktor V. Ivanishchev ◽  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Ascorbic Acid ◽  
Correlation Coefficients ◽  
Low Molecular Weight ◽  
Stress Indicators ◽  
Sodium Chloride Stress ◽  
Oxidative Stress Indicators

We studied the alterations in oxidative stress indicators (hydrogen peroxide, superoxide radical, lipid peroxidation – LPO) and the alterations in the content of low molecular weight metabolites (ascorbic acid, glutathione, proline, chlorophyll and carotenoids) in the shoots of triticale (Triticosecale) under short-term (0-96 h) sodium chloride stress (120 mM) with statistical methods: principal component analysis (PCA) and cluster analysis. An analysis of the alterations in oxidative stress indicators allowed us to calculate the correlation coefficients for the pairs: peroxide – superoxide (0.52), peroxide – LPO (0.62), superoxide – LPO (0.23). The inclusion in the analysis of data on alterations in the content of low molecular weight antioxidants showed that the PCA method forms three main groups for all the studied characteristics: (1) LPO and hydrogen peroxide, (2) chlorophyll and carotenoids, (3) glutathione and ascorbate. The correlation coefficients were calculated for pairs: ascorbate – glutathione (0.71), ascorbate – proline (0.81), glutathione – proline (0.28). Such a value of the coefficient of the first pair suggests that ascorbic acid also performs numerous other functions, in addition to participating in the ascorbate-glutathione cycle. The high correlation between ascorbate and proline can be explained by the similar nature of alterations in their content in triticale shoots under conditions of short-term sodium chloride stress. Negative correlation coefficients in pairs of hydrogen peroxide – chlorophyll (-0.73), peroxide – carotenoids (-0.75), ascorbic acid – LPO (-0.70), LPO – proline (-0.69) give reason to talk about the possible protective role of photosynthesis pigments from accumulating hydrogen peroxide, as well as the potential role of ascorbic acid and proline in protecting membranes from lipid peroxidation. The application of the cluster analysis method showed that first and second order clusters between ascorbate, proline and glutathione reflect their known antioxidant role. The results obtained may also indicate that pigments have a much lower protective function.

scholarly journals Possible Role of Hydrogen Peroxide in Apoptosis Induction by Ascorbic Acid in Human Myelogenous Leukemic Cell Lines

1994 ◽  
Vol 6 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Satoru FUJINAGA ◽  
Hiroshi SAKAGAMI ◽  
Nobuyuki KURIBAYASHI ◽  
Hideo TAKAHASHI ◽  
Yasuyuki AMANO ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Cell Lines ◽  
Leukemic Cell ◽  
Apoptosis Induction ◽  
Leukemic Cell Lines

The Involvement of Nitric Oxide and Hydrogen Peroxide in eATP-Inhibited Pollen Germination and Tube Growth of Paulownia Tomentosa In Vitro

2011 ◽  
Vol 343-344 ◽  
pp. 347-350
Author(s):  
Yuan Hua Zhang ◽  
Xiao Ping She
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Pollen Germination ◽  
Tube Growth ◽  
Paulownia Tomentosa ◽  
In Vitro Pollen Germination ◽  
Nos Inhibitor

Role of nitric oxide(NO) and hydrogen peroxide(H2O2) in eATP-inhibited reduction of in vitro pollen germination and tube growth of Paulownia tomentosa Steud. were studied. Results showed that exposure of the pollen to a series of eATP (0.2, 0.4, 0.6, 0.8, 1.0 mM) concentration for 3h resulted in not only the reduction of pollen germination but also the reduction of tube growth. Also, NOS inhibitor NG-nitro-L-Arg-methyl eater (L-NAME ), NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3- oxide(c-PTIO) and two scavengers of H2O2, ascorbic acid (ASC) and catalase (CAT) not only largely prevented eATP-inhibited pollen germination but also tube growth. These results indicated that NO and H2O2are involved in eATP inhibited pollen germination and tube growth.

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

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