Kinetic studies of copper-induced oxidation of urate, ascorbate and their mixtures

Samocha-Bonet, Dorit; Lichtenberg, Dov; Pinchuk, Ilya

doi:10.1016/j.jinorgbio.2005.06.006

Cited by 8 publications

(5 citation statements)

References 36 publications

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“…Zinc ions were less inhibitory, but still reduced enzyme activity by 92% (data not shown). Copper ions, when present at 2∶1 molar ratio with uric acid, have been reported to be responsible for the oxidation of uric acid [18]. In order to confirm that the copper was not altering the production of 5-HIU, we monitored 5-HIU production following equilibration of uricase with copper.…”

Section: Resultsmentioning

confidence: 99%

Salmonella Typhimurium's Transthyretin-Like Protein Is a Host-Specific Factor Important in Fecal Survival in Chickens

et al. 2012

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The transthyretin-like protein (TLP) from Salmonella enterica subspecies I is a periplasmic protein with high level structural similarity to a protein found in mammals and fish. In humans, the protein homologue, transthyretin, binds and carries retinol and thyroxine, and a series of other, unrelated aromatic compounds. Here we show that the amino acid sequence of the TLP from different species, subspecies and serovars of the Salmonella genus is highly conserved and demonstrate that the TLP gene is constitutively expressed in S. Typhimurium and that copper and other divalent metal ions severely inhibit enzyme activity of the TLP, a cyclic amidohydrolase that hydrolyses 5-hydroxyisourate (5-HIU). In order to determine the in vivo role of the S. Typhimurium TLP, we constructed a strain of mouse-virulent S. Typhimurium SL1344 bearing a mutation in the TLP gene (SL1344 ΔyedX). We assessed the virulence of this strain via oral inoculation of mice and chickens. Whilst SL1344 ΔyedX induced a systemic infection in both organisms, the bacterial load detected in the faeces of infected chickens was significantly reduced when compared to the load of S. Typhimurium SL1344. These data demonstrate that the TLP gene is required for survival of S. Typhimurium in a high uric acid environment such as chicken faeces, and that metabolic traits of Salmonellae in natural and contrived hosts may be fundamentally different. Our data also highlight the importance of using appropriate animal models for the study of bacterial pathogenesis especially where host-specific virulence factors or traits are the subject of the study.

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Section: Resultsmentioning

confidence: 99%

Salmonella Typhimurium's Transthyretin-Like Protein Is a Host-Specific Factor Important in Fecal Survival in Chickens

et al. 2012

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“…Uric acid is also pro‐oxidative when other antioxidants, such as ascorbate, are at low levels. Ascorbate prevents pro‐oxidant effects of urate in oxidation of human low‐density lipoproteins and inhibits urate's transition‐metal, ion‐induced oxidation (77,78). It is probably why a 50% reduction of ascorbate and no changes in the urate level were observed after massive injection of poly‐Hb (50).…”

Section: Discussionmentioning

confidence: 99%

Control of Oxidative Reactions of Hemoglobin in the Design of Blood Substitutes: Role of the Ascorbate–Glutathione Antioxidant System

et al. 2009

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Uncontrolled oxidative reactions of hemoglobin (Hb) are still the main unresolved problem for Hb-based blood substitute developers. Spontaneous oxidation of acellular ferrous Hb into a nonfunctional ferric Hb generates superoxide anion. Hydrogen peroxide, formed after superoxide anion dismutation, may react with ferrous/ferric Hb to produce toxic ferryl Hb, fluorescent heme degradation products, and/or protein-based free radicals. In the presence of free iron released from heme, superoxide anion and hydrogen peroxide might react via the Haber-Weiss and Fenton reactions to generate the hydroxyl radical. These highly reactive oxygen and heme species may not only be involved in shifting the cellular redox balance to the oxidized state that facilitates signal transduction and pro-inflammatory gene expression, but could also be involved in cellular and organ injury, and generation of vasoactive compounds such as isoprostanes and angiotensins. It is believed that these toxic species may be formed after administration of Hb-based blood substitutes, particularly in ischemic patients with a diminished ability to control oxidative reactions. Although varieties of antioxidant strategies have been suggested, this in vitro study examined the ability of the ascorbate-glutathione antioxidant system in preventing Hb oxidation and formation of its ferryl intermediate. The results suggest that although ascorbate is effective in reducing the formation of ferryl Hb, glutathione protects heme against excessive oxidation. Ascorbate without glutathione failed to protect the red blood cell membranes against Hb/hydrogen peroxide-mediated peroxidation. This study provides evidence that the ascorbate-glutathione antioxidant system is essential in attenuation of the pro-oxidant potential of redox active acellular Hbs, and superior to either ascorbate or glutathione alone.

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“…The oxidative effects of ua mainly manifest in mediating the immune response after cell injury (75), increasing pro-inflammatory immune activation (76) and promoting low-density lipoprotein oxidation (77), the proliferation of smooth muscle cells and activation and the adhesion of platelets (78). in the presence of cu 2+ in the in vitro environment, ua is susceptible to antioxidant-oxidant interconversion (79,80). in addition, ua can react with other oxidants (onoo − , oH − ) and form pro-oxidants, which participate in lipid metabolism and cause a chain reaction of lipophilic radical oxidation (81,82).…”

Section: Metabolism and Biological Characteristics Of Uamentioning

confidence: 99%

Insights into the relationship between serum uric acid and pulmonary hypertension (Review)

Zhou,

Chen,

Zheng

et al. 2023

Mol Med Rep

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Pulmonary hypertension (PH) is a progressive lethal disease, which is characterized by abnormal vascular remodeling and persistently elevated pulmonary artery pressure, eventually leading to right heart failure and even death. although great progress has been made in treating PH, the mortality rate remains high. Metabolic disorders are one of the important hallmarks of PH. obesity, lipids, glucose tolerance and insulin resistance are risk factors for numerous cardiovascular diseases and are often accompanied by a considerable increase in serum uric acid (Sua) concentrations. uric acid (ua) is the end product of purine nucleotide metabolism and is closely related to cardiovascular diseases including PH. Hyperuricemia promotes the development and progression of PH through endothelial dysfunction, oxidative stress, inflammatory responses and activation of the renin-angiotensin system. in the present review, the advancements in knowledge about ua metabolism and PH, and the current understanding of the potential interactions and mechanisms of Sua in PH were systematically summarized, which may provide new insights into the pathogenesis of PH.

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Kinetic studies of copper-induced oxidation of urate, ascorbate and their mixtures

Cited by 8 publications

References 36 publications

Salmonella Typhimurium's Transthyretin-Like Protein Is a Host-Specific Factor Important in Fecal Survival in Chickens

Salmonella Typhimurium's Transthyretin-Like Protein Is a Host-Specific Factor Important in Fecal Survival in Chickens

Control of Oxidative Reactions of Hemoglobin in the Design of Blood Substitutes: Role of the Ascorbate–Glutathione Antioxidant System

Insights into the relationship between serum uric acid and pulmonary hypertension (Review)

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