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Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation
Published on: March 9, 2018
Trivalent arsenicals are bound to proteins during reductive methylation
Hua Naranmandura1, Noriyuki Suzuki, Kazuo T Suzuki
1Graduate School of Pharmaceutical Sciences, Chiba University, Chuo, Chiba 260-8675, Japan.
Inorganic arsenic methylation in rats occurs reductively, not oxidatively. Arsenic binds to proteins in trivalent forms, with pentavalent metabolites being end products, not intermediates.
Area of Science:
- Toxicology
- Biochemistry
- Environmental Health
Background:
- Inorganic arsenic is metabolized to methylated compounds, primarily excreted as dimethylarsinic acid.
- Understanding arsenic metabolism is crucial for assessing its toxicity and health risks.
Purpose of the Study:
- To investigate the metabolism of arsenic in rat liver and kidneys.
- To identify hepatic and renal arsenic metabolites after intravenous arsenite injection.
Main Methods:
- Intravenous injection of arsenite in rats.
- Fractionation of liver and kidney tissues into soluble and sediment components.
- Analysis of arsenic species using hydrogen peroxide oxidation and high-performance liquid chromatography.
Main Results:
- Arsenic was found in both soluble and sediment fractions, predominantly bound to high molecular weight proteins.
- Oxidation released pentavalent forms: arsenate, monomethylarsonic acid (MMA(V)), and dimethylarsinic acid (DMA(V)).
- Arsenic metabolites bound to proteins were in trivalent forms, suggesting reductive methylation.
Conclusions:
- Arsenic methylation proceeds via a reductive pathway involving glutathione, not stepwise oxidative methylation.
- Pentavalent arsenicals (MMA(V) and DMA(V)) are end products, not metabolic intermediates.
- In vitro studies indicated potential formation of dimethylthioarsenicals.
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