Role of 2,4-Dichlorophenol in the Oxidation of Estradiol by Uterine and Horseradish Peroxidase

1973 ◽  
Vol 51 (7) ◽  
pp. 1066-1071 ◽  
Author(s):  
C. R. Lyttle ◽  
T. McNabb ◽  
P. H. Jellinck
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Water Soluble

The role of 2,4-dichlorophenol in enhancing the conversion of [4-14C]estradiol to water-soluble products by a uterine preparation in the presence of hydrogen peroxide has been investigated. The addition of this phenol to a solution of uterine or horseradish peroxidase in 8 M urea restored the activity of the enzyme and also that of horseradish peroxidase inactivated by heating. It also protected the enzyme from inactivation during incubation. It is proposed that 2,4-dichlorophenol exerts its effect by activating peroxidase and protecting the enzyme from inactivation by the products of the reaction.

scholarly journals Inhibitory effect of retinol acetate on horseradish peroxidase

2013 ◽  
Vol 67 (3) ◽  
pp. 419-426
Author(s):  
Vladan Djuric ◽  
Nebojsa Deletic ◽  
Vesna Stankov-Jovanovic ◽  
Ranko Simonovic
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Enzymatic Reaction ◽  
Inhibitory Effect ◽  
Enzyme Concentration ◽  
Water Soluble ◽  
Primary Role ◽  
Retinol Acetate ◽  
Peroxidase Enzyme

Primary role of peroxidase enzyme is to decompose endogenous hydrogen peroxide, when oxygen radical is being replaced by a less potent radical, which is its cosubstrates oxidized form. During this study, catalytic activity of horseradish peroxidase has been observed in the presence of antioxidants from vitamin group, such as C, E and A, i.e. their water-soluble forms. It was found that vitamin E showed no effect on the enzyme activity and fate of cosubstrate radicals from the group of benzidine derivatives. Vitamin C proceeds enzymatic reaction showing its antioxidative character, and absorbs electrons from radicals, bringing cosubstrate back to its relaxed state. On the other hand, vitamin A plays a role of uncompetitive peroxidase inhibitor, which is visible through decreasing initial rate of catalytic reaction, and is reflected as virtual decrease of enzyme concentration. Furthermore, it prolongs life of endogenous hydrogen peroxide, which could potentially lead to oxidative stress of cells. This inhibitory effect can be used in analytical purpose, for determination of retinol acetate content in a sample.

Role of peroxidase and chitosan in removing chlorophenols from aqueous solution

1996 ◽  
Vol 34 (10) ◽  
pp. 151-159 ◽  
Author(s):  
Hossein Ganjidoust ◽  
Kenji Tatsumi ◽  
Shinji Wada ◽  
Mitsuo Kawase
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Horseradish Peroxidase ◽  
Industrial Wastewater ◽  
Aluminum Sulfate ◽  
Enzymatic Reaction ◽  
Hexamethylene Diamine ◽  
Natural Coagulant

Chlorophenols removal from industrial wastewater by horseradish peroxidase and coagulant was investigated. It was found that an enzymatic reaction time of less than one hour was enough for the reaction to reach 95% completion. Chitosan, which is a natural coagulant, was an effective coagulant as compared to mineral coagulants such as aluminum sulfate (ALUM), hexamethylene diamine epichlorohydrin polycondensate (HX), polyacrylamide (PAM), and polyethyleneimine (PEI). A combination of 0.4 U/mL peroxidase to 2 ppm chitosan along with 0.8 mM of hydrogen peroxide resulted in over 95% chlorophenol removal from aqueous solution.

Interaction of [4-14C]Estradiol and its Metabolites with Polynucleotides in the Presence of Peroxidase

1971 ◽  
Vol 49 (8) ◽  
pp. 885-890 ◽  
Author(s):  
P. H. Jellinck ◽  
Rosemarie Fletcher
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Water Soluble ◽  
Rat Uterus ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid

Incubation of [4-14C]estradiol with either horseradish peroxidase or uterine preparations resulted in the formation of water-soluble products if certain polynucleotides were also present. It was shown that both systems required hydrogen peroxide and that binding of the steroids occurred more readily with DNA or polyadenylic acid than with RNA or polyuridylic acid. The 14C radioactivity associated with the polynucleotides was present in unidentified metabolites and a small amount of unchanged estradiol. These products were bound weakly and could be removed by mild procedures in contrast to the conjugates formed with albumin or thiols by this system. The significance of the action of peroxidase in the binding of estrogens in rat uterus is discussed.

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.

Neurotoxicity and Neuroprotective Effects of Polyimides (PI) and Polyphenylenevinylene (PPV) against Hydrogen Peroxide (H2O2)

2011 ◽  
Vol 8 (2) ◽  
pp. 33
Author(s):  
Norfaezah Mazalan ◽  
Mazatulikhma Mat Zain ◽  
Nor Saliyana Jumali ◽  
Norhanim Mohalid ◽  
Zurina Shaameri ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Drug Delivery Systems ◽  
Neuronal Cells ◽  
Water Soluble ◽  
Brain Delivery ◽  
Specific Therapy ◽  
Neuroprotective Effects ◽  
Water Soluble Polymer ◽  
Site Specific ◽  
Novel Drugs

Recently, research and development in the field of drug delivery systems (DDS) facilitating site-specific therapy has reached significant progression. DDS based on polymer micelles, coated micro- and nanoparticles, and various prodrug systems including water-soluble polymer have been prepared and extensively studied as novel drugs designed for cancer chemotherapy and brain delivery. Since polymers are going to be used in human, this study has the interest of testing two types of polymer, polyimides (PI) and polyphenylenevinylene (PPV) on neuronal cells. The objective of this study was to determine the possible neurotoxicity and potential neuroprotective effects of PI and PPV towards SH-SY5Y neuronal cells challenged by hydrogen peroxide (H2O2) as an oxidant. Cells were pretreated with either PI or PPV for 1 hour followed by incubation for 24 hour with 100 µM of H2O2. MTS assay was used to assess cell viability. Results show that PI and PPV are not harmful within the concentration up to 10 µM and 100 µM, respectively. However, PI and PPV do not protect neuronal cells against toxicity induced by H2O2 or further up the cell death.

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.

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