scholarly journals Monovalent Copper Ions Inhibit Enzymatic Systems

2021 ◽  
Author(s):  
Magal Saphier ◽  
Lea Moshkovich ◽  
Stanislav Popov ◽  
Yoram Shotland ◽  
Eldad Silberstein ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Acid Phosphatase ◽  
Dna Polymerase ◽  
Restriction Enzyme ◽  
Copper Ions ◽  
Divalent Copper ◽  
Nitrogen Base ◽  
Monovalent Ions ◽  
Wide Range ◽  
Enzymatic Systems

Abstract The effect of monovalent copper ions on enzymatic systems has hardly been studied to date; this is due to the low stability of monovalent copper ions in aqueous solutions, which led to the assumption that their concentration is negligible in biological systems. However, in an anaerobic atmosphere, and in the presence of a ligand that stabilizes the monovalent copper ions over the divalent copper ions, high and stable concentrations of monovalent copper ions can be reached. Moreover, the cell cytoplasm has a substantial concentration of potential stabilizers that can explain significant concentrations of monovalent copper ions in the cytoplasm. This study demonstrates the effect of monovalent and divalent copper ions on DNA polymerase, ligaseT4 DNA, the restriction enzymes EcoP15I and EcoR I, acid phosphatase, and α and βamylase enzymes. These systems were chosen because they can be monitored under conditions necessary for maintaining a stable concentration of monovalent copper ions, and since they exhibit a wide range of dependency on ATP. Previous studies indicated that ATP interacts with monovalent and divalent copper ions and stabilizing monovalent copper ions over divalent copper ions. The results showed that monovalent copper ions dramatically inhibit DNA polymerase and acid phosphatase, inhibit ligaseT4 DNA and the restriction enzyme EcoP15I, moderately inhibit α and β amylase, and have no effect on the restriction enzyme EcoR I. From the results presented in this work, it can be concluded that the mechanism is not one of oxidative stress, even though monovalent copper ions generate reactive oxygen species (ROS). Molecular oxygen in the medium, which is supposed to increase the oxidative stress, impairs the inhibitory effect of monovalent and divalent copper ions, and the kinetics of the inhibition is not suitable for the ROS mechanism.ATP forms a complex with copper ions (di and monovalent ions, where the latter is more stable) in which the metal ion is bound both to the nitrogen base and to the oxygen charged on the phosphate groups, forming an unusually distorted complex. The results of this study indicate that these complexes have the ability to inhibit enzymatic systems that are dependent on ATP.This finding can provide an explanation for the strong antimicrobial activity of monovalent copper ions, suggesting that rapid and lethal metabolic damage is the main mechanism of monovalent copper ions’ antimicrobial effect.

scholarly journals Reduction of Protein Bound Methionine Sulfoxide by a Periplasmic Dimethyl Sulfoxide Reductase

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 616
Author(s):  
Lionel Tarrago ◽  
Sandrine Grosse ◽  
David Lemaire ◽  
Laetitia Faure ◽  
Mathilde Tribout ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amino Acid ◽  
Dimethyl Sulfoxide ◽  
Free Amino Acid ◽  
Free Amino ◽  
Methionine Sulfoxide ◽  
Methionine Sulfoxide Reductases ◽  
Wide Range ◽  
Enzymatic Systems ◽  
Protein Functions

In proteins, methionine (Met) can be oxidized into Met sulfoxide (MetO). The ubiquitous methionine sulfoxide reductases (Msr) A and B are thiol-oxidoreductases reducing MetO. Reversible Met oxidation has a wide range of consequences, from protection against oxidative stress to fine-tuned regulation of protein functions. Bacteria distinguish themselves by the production of molybdenum-containing enzymes reducing MetO, such as the periplasmic MsrP which protects proteins during acute oxidative stress. The versatile dimethyl sulfoxide (DMSO) reductases were shown to reduce the free amino acid MetO, but their ability to reduce MetO within proteins was never evaluated. Here, using model oxidized proteins and peptides, enzymatic and mass spectrometry approaches, we showed that the Rhodobacter sphaeroides periplasmic DorA-type DMSO reductase reduces protein bound MetO as efficiently as the free amino acid L-MetO and with catalytic values in the range of those described for the canonical Msrs. The identification of this fourth type of enzyme able to reduce MetO in proteins, conserved across proteobacteria and actinobacteria, suggests that organisms employ enzymatic systems yet undiscovered to regulate protein oxidation states.

scholarly journals Oxidative status in plasma, urine and saliva of girls with anorexia nervosa and healthy controls: a cross-sectional study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Gaál Kovalčíková ◽  
Ľubica Tichá ◽  
Katarína Šebeková ◽  
Peter Celec ◽  
Alžbeta Čagalová ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Anorexia Nervosa ◽  
Redox Homeostasis ◽  
Oxidative Status ◽  
Carbonyl Stress ◽  
Healthy Controls ◽  
Psychosomatic Disorder ◽  
Cross Sectional ◽  
Wide Range ◽  
Markers Of Oxidative Stress

Abstract Background Anorexia nervosa (AN) is a serious psychosomatic disorder with unclear pathomechanisms. Metabolic dysregulation is associated with disruption of redox homeostasis that might play a pivotal role in the development of AN. The aim of our study was to assess oxidative status and carbonyl stress in plasma, urine and saliva of patients with AN and healthy controls. Methods Plasma, spot urine, and saliva were collected from 111 girls with AN (aged from 10 to 18 years) and from 29 age-matched controls. Markers of oxidative stress and antioxidant status were measured using spectrophotometric and fluorometric methods. Results Plasma advanced oxidation protein products (AOPP) and advanced glycation end products (AGEs) were significantly higher in patients with AN than in healthy controls (by 96, and 82%, respectively). Accordingly, urinary concentrations of AOPP and fructosamines and salivary concentrations of AGEs were higher in girls with AN compared with controls (by 250, and 41% in urine; by 92% in saliva, respectively). Concentrations of thiobarbituric acid reactive substances (TBARS) in saliva were 3-times higher in the patients with AN than in the controls. Overall antioxidants were lower in plasma of girls with AN compared to the controls, as shown by total antioxidant capacity and ratio of reduced and oxidized glutathione (by 43, and 31%, respectively). Conclusions This is the first study assessing wide range of markers of oxidative status in plasma, urine and saliva of the patients with AN. We showed that both, higher levels of markers of oxidative stress and lower antioxidants play a role in redox disruption. Restoration of redox homeostasis might be of the clinical relevance

scholarly journals Oxygen Is Instrumental for Biological Signaling: An Overview

Oxygen ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 3-15
Author(s):  
John T. Hancock
Keyword(s):  
Oxidative Stress ◽  
Superoxide Anion ◽  
Nitrosative Stress ◽  
Redox Status ◽  
Complex Interplay ◽  
Wide Range ◽  
Form Part ◽  
High Concentrations ◽  
And Control ◽  
Signaling Components

Control of cellular function is extremely complex, being reliant on a wide range of components. Several of these are small oxygen-based molecules. Although reactive compounds containing oxygen are usually harmful to cells when accumulated to relatively high concentrations, they are also instrumental in the control of the activity of a myriad of proteins, and control both the upregulation and downregulation of gene expression. The formation of one oxygen-based molecule, such as the superoxide anion, can lead to a cascade of downstream generation of others, such as hydrogen peroxide (H2O2) and the hydroxyl radical (∙OH), each with their own reactivity and effect. Nitrogen-based signaling molecules also contain oxygen, and include nitric oxide (NO) and peroxynitrite, both instrumental among the suite of cell signaling components. These molecules do not act alone, but form part of a complex interplay of reactions, including with several sulfur-based compounds, such as glutathione and hydrogen sulfide (H2S). Overaccumulation of oxygen-based reactive compounds may alter the redox status of the cell and lead to programmed cell death, in processes referred to as oxidative stress, or nitrosative stress (for nitrogen-based molecules). Here, an overview of the main oxygen-based molecules involved, and the ramifications of their production, is given.

scholarly journals Neurological Alterations and Testicular Damages in Aging Induced by D-Galactose and Neuro and Testicular Protective Effects of Combinations of Chitosan Nanoparticles, Resveratrol and Quercetin in Male Mice

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 435
Author(s):  
Reham Z. Hamza ◽  
Mohammad S. Al-Harbi ◽  
Munirah A. Al-Hazaa
Keyword(s):  
Oxidative Stress ◽  
Chitosan Nanoparticles ◽  
Oxidative Stress Marker ◽  
Control Group ◽  
Antioxidant Enzyme Activities ◽  
Enzymatic Antioxidants ◽  
Protective Effects ◽  
Biochemical Alterations ◽  
Wide Range ◽  
Neurological Alterations

Aging is a neurological disease that is afforded by incidence of oxidative stress. Chitosan has received global interests due to its wide medical uses. Quercetin (Q) is a bioflavonoid and widely distributed in vegetables and fruits. Resveratrol is considered as a potent antioxidant and is a component of a wide range of foods. The using of either chitosan nanopartciles (CH-NPs), querectin (Q), and resveratrol (RV) to reduce the oxidative stress and biochemical alterations on brain and testicular tissues induced by D-galactose (DG) (100 mg/Kg) were the aim of the present study. This study investigated the probable protective effects of CH-NPs in two doses (140,280 mg/Kg), Q (20 mg/Kg) and RV (20 mg/Kg), against DG induced aging and neurological alterations. Brain antioxidant capacity as malonaldehyde (MDA), catalase (CAT), and glutathione reductase (GRx), as well as histopathological damages of the brain and testicular tissues were measured. The DG treated group had significantly elevated the oxidative stress markers by 96% and 91.4% in brain and testicular tissues respectively and lower significantly the antioxidant enzyme activities of both brain and testicular tissues than those of the control group by 86.95%, 69.27%, 83.07%, and 69.43%. Groups of DG that treated with a combination of CH-NPs in two doses, Q and RV, the levels of oxidative stress marker declined significantly by 68.70%, 76.64% in brain tissues and by 74.07% and 76.61% in testicular tissues, and the enzymatic antioxidants increased significantly by 75.55%, 79.24%, 62.32%, and 61.97% as compared to the DG group. The present results indicate that CH-NPs, Q, and RV have protective effects against DG-induced brain and testis tissue damage at the biochemical and histopathological levels. Mechanisms of this protective effect of used compounds against neurological and testicular toxicity may be due to the enhanced brain and testis antioxidant capacities.

scholarly journals FlashPlate Scintillation Proximity Assays for Characterization and Screening of DNA Polymerase, Primase, and Helicase Activities

2001 ◽  
Vol 6 (1) ◽  
pp. 39-46 ◽  
Author(s):  
David L. Earnshaw ◽  
Andrew J. Pope
Keyword(s):  
Dna Polymerase ◽  
Drug Targets ◽  
Direct Synthesis ◽  
Enzyme Characterization ◽  
Dna Helicase ◽  
Oligonucleotide Primer ◽  
Replication Proteins ◽  
Dna Primase ◽  
Wide Range ◽  
Complementary Oligonucleotide

DNA replication proteins represent a class of extremely well-established anti-infective drug targets for which improvements in assay technology are required in order to support enzyme characterization, HTS, and structure-activity relationship studies. Replication proteins are conventionally assayed using precipitation/filtration or gelbased techniques, and are not yet all suitable for conversion into homogeneous fluorescence-based formats. We have therefore developed radiometric assays for these enzymes based upon FlashPlate technology that can be applied to a wide range of targets using a common set of reagents. This approach has allowed the rapid characterization of DNA polymerase, DNA primase, and DNA helicase activities. The resultant 96-/384-well microplate assays are suitable for primary HTS, hit selectivity determination, and/or elucidating the mechanism of action of inhibitors. In all cases, biotinylated DNA oligonucleotide substrates were tethered to streptavidin-coated scintillant-embedded FlashPlate wells. Various adaptations were employed for each enzyme activity. For DNA polymerase, a short complementary oligonucleotide primer was annealed to the longer tethered oligonucleotide, and polymerization was measured by incorporation of [3H]-dNTPs onto the growing primer 3′ end. For DNA primase, direct synthesis of short oligoribonucleotides complementary to the tethered DNA strand was measured by incorporation of [3H]-rNTPs or by subsequent polymerase extension with [3H]-dNTPs from unlabeled primers. For DNA helicase, unwinding of a [33P]-labeled oligonucleotide complementary to the tethered oligonucleotide was measured. This robust and flexible system has a number of substantial advantages over conventional assay techniques for this difficult class of enzymes.

scholarly journals Tamoxifen and oxidative stress: an overlooked connection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nermin S. Ahmed ◽  
Marek Samec ◽  
Alena Liskova ◽  
Peter Kubatka ◽  
Luciano Saso
Keyword(s):  
Breast Cancer ◽  
Oxidative Stress ◽  
Gold Standard ◽  
Pharmacological Activities ◽  
Standard Drug ◽  
Menopausal Women ◽  
Wide Range ◽  
Post Menopausal ◽  
Apoptotic Effects ◽  
And Oxidative Stress

AbstractTamoxifen is the gold standard drug for the treatment of breast cancer in pre and post-menopausal women. Its journey from a failing contraceptive to a blockbuster is an example of pharmaceutical innovation challenges. Tamoxifen has a wide range of pharmacological activities; a drug that was initially thought to work via a simple Estrogen receptor (ER) mechanism was proven to mediate its activity through several non-ER mechanisms. Here in we review the previous literature describing ER and non-ER targets of tamoxifen, we highlighted the overlooked connection between tamoxifen, tamoxifen apoptotic effects and oxidative stress.

scholarly journals Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

1972 ◽  
Vol 127 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. G. Bolton ◽  
A. C. R. Dean
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Continuous Culture ◽  
Activity Profile ◽  
Glucose Effect ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Wide Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined.

scholarly journals Maternal Urinary Metal and Metalloid Concentrations in Association with Oxidative Stress Biomarkers

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 114
Author(s):  
Pahriya Ashrap ◽  
Deborah J. Watkins ◽  
Ginger L. Milne ◽  
Kelly K. Ferguson ◽  
Rita Loch-Caruso ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Prostaglandin F2α ◽  
Urine Samples ◽  
Oxidative Stress Marker ◽  
Essential Metals ◽  
Male Fetus ◽  
Metal Concentrations ◽  
Fetal Sex ◽  
Wide Range ◽  
And Oxidative Stress

Metal exposure has been associated with a wide range of adverse birth outcomes and oxidative stress is a leading hypothesis of the mechanism of action of metal toxicity. We assessed the relationship between maternal exposure to essential and non-essential metals and metalloids in pregnancy and oxidative stress markers, and sought to identify windows of vulnerability and effect modification by fetal sex. In our analysis of 215 women from the PROTECT birth cohort study, we measured 14 essential and non-essential metals in urine samples at three time points during pregnancy. The oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite 2,3-dinor-5,6-dihydro-15-15-F2t-IsoP, as well as prostaglandin F2α (PGF2α), were also measured in the same urine samples. Using linear mixed models, we examined the main effects of metals on markers of oxidative stress as well as the visit-specific and fetal sex-specific effects. After adjustment for covariates, we found that a few urinary metal concentrations, most notably cesium (Cs) and copper (Cu), were associated with higher 8-iso-PGF2α with effect estimates ranging from 7.3 to 14.9% for each interquartile range, increase in the metal concentration. The effect estimates were generally in the same direction at the three visits and a few were significant only among women carrying a male fetus. Our data show that higher urinary metal concentrations were associated with elevated biomarkers of oxidative stress. Our results also indicate a potential vulnerability of women carrying a male fetus.

scholarly journals Fucoidan Alleviates Acetaminophen-Induced Hepatotoxicity via Oxidative Stress Inhibition and Nrf2 Translocation

2018 ◽  
Vol 19 (12) ◽  
pp. 4050 ◽  
Author(s):  
Yu-qin Wang ◽  
Jin-ge Wei ◽  
Meng-jue Tu ◽  
Jian-guo Gu ◽  
Wei Zhang
Keyword(s):  
Oxidative Stress ◽  
Serum Levels ◽  
Sulfated Polysaccharide ◽  
Intragastric Administration ◽  
Related Factor ◽  
Cell Nuclei ◽  
Brown Seaweeds ◽  
Wide Range ◽  
Related Proteins ◽  
Apap Hepatotoxicity

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug that leads to severe hepatotoxicity at excessive doses. Fucoidan, a sulfated polysaccharide derived from brown seaweeds, possesses a wide range of pharmacological properties. However, the impacts of fucoidan on APAP-induced liver injury have not been sufficiently addressed. In the present study, male Institute of Cancer Research (ICR) mice aged 6 weeks were subjected to a single APAP (500 mg/kg) intraperitoneal injection after 7 days of fucoidan (100 or 200 mg/kg/day) or bicyclol intragastric administration. The mice continued to be administered fucoidan or bicyclol once per day, and were sacrificed at an indicated time. The indexes evaluated included liver pathological changes, levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT) in the liver, and related proteins levels (CYP2E1, pJNK and Bax). Furthermore, human hepatocyte HL-7702 cell line was used to elucidate the potential molecular mechanism of fucoidan. The mitochondrial membrane potential (MMP) and nuclear factor-erythroid 2-related factor (Nrf2) translocation in HL-7702 cells were determined. The results showed that fucoidan pretreatment reduced the levels of ALT, AST, ROS, and MDA, while it enhanced the levels of GSH, SOD, and CAT activities. Additionally, oxidative stress-induced phosphorylated c-Jun N-terminal protein kinase (JNK) and decreased MMP were attenuated by fucoidan. Although the nuclear Nrf2 was induced after APAP incubation, fucoidan further enhanced Nrf2 in cell nuclei and total expression of Nrf2. These results indicated that fucoidan ameliorated APAP hepatotoxicity, and the mechanism might be related to Nrf2-mediated oxidative stress.

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