Arsenic

Rossman, Toby G.

doi:10.1002/9780470442890.ch11

Cited by 2 publications

(2 citation statements)

References 174 publications

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“…Exposure to As via drinking water is correlated with a significantly elevated risk of skin and bladder cancer (1). Inhalation exposure to arsenic is associated with an increased risk of lung cancer.…”

Section: Introductionmentioning

confidence: 99%

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In Vitro Effect of Arsenical Compounds on Glutathione-Related Enzymes

Chouchane

Snow

2001

Chem. Res. Toxicol.

113

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The mechanism of arsenic toxicity is believed to be due to the ability of arsenite (As(III)) to bind protein thiols. Glutathione (GSH) is the most abundant cellular thiol, and both GSH and GSH-related enzymes are important antioxidants that play an important role in the detoxification of arsenic and other carcinogens. The effect of arsenic on the activity of a variety of enzymes that use GSH has been determined using purified preparations of glutathione reductase (GR) from yeast and bovine glutathione peroxidase (GPx) and equine glutathione S-transferase (GST). The effect on enzyme activity of increasing concentrations (from 1 microM to 100 mM) of commercial sodium arsenite (As(III)) and sodium arsenate (As(V)) and a prepared arsenic(III)-glutathione complex [As(III)(GS)(3)] and methylarsenous diiodide (CH(3)As(III)) has been examined. GR, GPx, and GST are not sensitive to As(V) (IC(50) > 50 mM), and none of the enzymes are inhibited or activated by physiologically relevant concentrations of As(III), As(III)(GS)(3), or CH(3)As(III), although CH(3)As(III) is the most potent inhibitor (0.3 mM < IC(50) < 1.5 mM). GPx is the most sensitive to arsenic treatment and GST the least. Our results do not implicate a direct interaction of As with the glutathione-related enzymes, GR, GPx, and GST, in the mechanism of arsenic toxicity. CH(3)As(III) is the most effective inhibitor, but it is unclear whether this product of arsenic metabolism is produced at a sufficiently high concentration in critical target tissues to play a major role in either arsenic toxicity or carcinogenesis.

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Section: Introductionmentioning

confidence: 99%

“…Inorganic arsenic (As) 1 is an important environmental toxicant which has both natural and industrial sources. Exposure to As via drinking water is correlated with a significantly elevated risk of skin and bladder cancer (1). Inhalation exposure to arsenic is associated with an increased risk of lung cancer.…”

Section: Introductionmentioning

confidence: 99%

In Vitro Effect of Arsenical Compounds on Glutathione-Related Enzymes

Chouchane

Snow

2001

Chem. Res. Toxicol.

113

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Self-assembling thermostable chimeras as new platform for arsenic biosensing

Puopolo

Sorrentino

Gallo

et al. 2021

Sci Rep

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The correct immobilization and orientation of enzymes on nanosurfaces is a crucial step either for the realization of biosensors, as well as to guarantee the efficacy of the developed biomaterials. In this work we produced two versions of a chimeric protein, namely ArsC-Vmh2 and Vmh2-ArsC, which combined the self-assembling properties of Vmh2, a hydrophobin from Pleurotus ostreatus, with that of TtArsC, a thermophilic arsenate reductase from Thermus thermophilus; both chimeras were heterologously expressed in Escherichia coli and purified from inclusion bodies. They were characterized for their enzymatic capability to reduce As(V) into As(III), as well as for their immobilization properties on polystyrene and gold in comparison to the native TtArsC. The chimeric proteins immobilized on polystyrene can be reused up to three times and stored for 15 days with 50% of activity loss. Immobilization on gold electrodes showed that both chimeras follow a classic Langmuir isotherm model towards As(III) recognition, with an association constant (KAsIII) between As(III) and the immobilized enzyme, equal to 650 (± 100) L mol−1 for ArsC-Vmh2 and to 1200 (± 300) L mol−1 for Vmh2-ArsC. The results demonstrate that gold-immobilized ArsC-Vmh2 and Vmh2-ArsC can be exploited as electrochemical biosensors to detect As(III).

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Arsenic

Cited by 2 publications

References 174 publications

In Vitro Effect of Arsenical Compounds on Glutathione-Related Enzymes

In Vitro Effect of Arsenical Compounds on Glutathione-Related Enzymes

Self-assembling thermostable chimeras as new platform for arsenic biosensing

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