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a salt or ester of arsenic acid
a poisonous white solid (Pb3[AsO4]2) used as an insecticide

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/08/29 18:08:29」(JST)

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The arsenate ion is AsO₄³⁻. An arsenate (compound) is any compound that contains this ion. Arsenates are salts or esters of arsenic acid.

The arsenic atom in arsenate has a valency of 5 and is also known as pentavalent arsenic or As[V].

Arsenate resembles phosphate in many respects, since arsenic and phosphorus occur in the same group (column) of the periodic table.

Arsenates are moderate oxidizers, with an electrode potential of +0.56 for reduction to arsenites.

Occurrence

Arsenates occur naturally in a variety of minerals. Those minerals may contain hydrated or anhydrous arsenates. Unlike phosphates, arsenates are not lost from a mineral during weathering. Examples of arsenate-containing minerals include adamite, alarsite, annabergite, erythrite and legrandite.^[1]

Ions

In strongly acidic conditions it exists as arsenic acid, H₃AsO₄;
in weakly acidic conditions it exists as dihydrogen arsenate ion, H₂AsO₄⁻;
in weakly basic conditions it exists as hydrogen arsenate ion HAsO₄²⁻;
and finally, in strongly basic conditions, it exists as the arsenate ion AsO₄³⁻.

Arsenate poisoning

Arsenate can replace inorganic phosphate in the step of glycolysis that produces 1,3-bisphosphoglycerate from glyceraldehyde 3-phosphate. This yields 1-arseno-3-phosphoglycerate instead, which is unstable and quickly hydrolyzes, forming the next intermediate in the pathway, 3-phosphoglycerate. Therefore glycolysis proceeds, but the ATP molecule that would be generated from 1,3-bisphosphoglycerate is lost - arsenate is an uncoupler of glycolysis, explaining its toxicity.^[2]

As with other arsenic compounds, arsenate can also inhibit the conversion of pyruvate into acetyl-CoA, blocking the Krebs cycle and therefore resulting in further loss of ATP.^[3]

Bacteria using and generating arsenate

Some species of bacteria obtain their energy by oxidizing various fuels while reducing arsenates to form arsenites. The enzymes involved are known as arsenate reductases.

In 2008, bacteria were discovered that employ a version of photosynthesis with arsenites as electron donors, producing arsenates (just like ordinary photosynthesis uses water as electron donor, producing molecular oxygen). The researchers conjectured that historically these photosynthesizing organisms produced the arsenates that allowed the arsenate-reducing bacteria to thrive.^[4]

In 2010, a team at NASA's Astrobiology Institute cultured samples of arsenic-resistant GFAJ-1 bacteria from Mono Lake, using a medium high in arsenate and low in phosphate concentration. The findings suggest that the bacteria may partially incorporate arsenate in place of phosphate in some biomolecules, including DNA,^[5]^[6] However, these claims were immediately debated and critiqued in correspondence to the original journal of publication,^[7] and have since come to be widely disbelieved.^[8] Reports refuting the most significant aspects of the original results have been published in the journal of the original research in 2012, including by researchers from the University of British Columbia and Princeton University.^[9]^[10] Following the publication of the articles challenging the conclusions of the original Science article first describing GFAJ-1 it was argued that the original article should be retracted because of misrepesentation of critical data.^[11]

References

^ Mineralienatlas - Mineralklasse Phosphate, Arsenate, Vanadate. (German)
^ Hughes, Michael F. (2002). "Arsenic toxicity and potential mechanisms of action". Toxicology Letters (133): 4.
^ Kim Gehle; Selene Chou; William S. Beckett (2009-10-01), Arsenic Toxicity Case Study, Agency for Toxic Substances and Disease Registry
^ Arsenic-loving bacteria rewrite photosynthesis rules, Chemistry World, 15 August 2008
^ A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus. Wolfe-Simon F, Blum JS, Kulp TR, Gordon GW, Hoeft SE, Pett-Rdige J, Stolz JF, Webb SM, Weber PK, Davies PCW, Anbar AD, Oremland RS. Science Express. 2 December 2010.
^ NASA Finds New Arsenic-Based Life Form in California, Wired Science, 2 December 2010
^ Wolfe-Simon, F., Blum, J.S., Kulp, T.R., Gordon, G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D. & Oremland, R.S. Response to Comments on "A Bacterium That Can Grow Using Arsenic Instead of Phosphorus", Science, 27 May 2011, and references therein. Bibcode 2011Sci...332.1149W. doi:10.1126/science.1202098. Accessed 30 May 2011
^ Drahl, C. The Arsenic-Based-Life Aftermath. Researchers challenge a sensational claim, while others revisit arsenic biochemistry, Chem Eng News 90(5), 42-47, 30 January 2012. http://cen.acs.org/articles/90/i5/Arsenic-Based-Life-Aftermath.html; accessed 13 October 2012
^ Science. 8 July 2012. GFAJ-1 Is an Arsenate-Resistant, Phosphate-Dependent Organism. doi: 10.1126/science.1218455. Accessed 10 July 2012.
^ Science. 8 July 2012. Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells.
^ http://retractionwatch.wordpress.com/2012/07/09/despite-refutation-science-arsenic-life-paper-deserves-retraction-scientist-argues/#comments

UpToDate Contents

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1. ヒ素曝露と中毒 arsenic exposure and poisoning
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4. 殺鼠剤中毒の概要 overview of rodenticide poisoning
5. 小児における後天性末梢性ニューロパチーの概要 overview of acquired peripheral neuropathies in children

English Journal

Arsenic-resistant bacteria solubilized arsenic in the growth media and increased growth of arsenic hyperaccumulator Pteris vittata L.

Ghosh P, Rathinasabapathi B, Ma LQ.SourceSoil and Water Science Department, University of Florida, Gainesville, FL 32611, United States.
Bioresource technology.Bioresour Technol.2011 Oct;102(19):8756-61. Epub 2011 Jul 24.
The role of arsenic-resistant bacteria (ARB) in arsenic solubilization from growth media and growth enhancement of arsenic-hyperaccumulator Pteris vittata L. was examined. Seven ARB (tolerant to 10mM arsenate) were isolated from the P. vittata rhizosphere and identified by 16S rRNA sequencing as Pse
PMID 21840210

Phloem transport of arsenic species from flag leaf to grain during grain filling.

Carey AM, Norton GJ, Deacon C, Scheckel KG, Lombi E, Punshon T, Guerinot ML, Lanzirotti A, Newville M, Choi Y, Price AH, Meharg AA.SourceInstitute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK National Risk Management Research Laboratory, US Environmental Protection Agency, 5995 Centre Hill Avenue, Cincinnati, OH 45224, USA Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus Mawson Lakes, S. Australia, SA-5095 Australia Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA Centre for Advanced Radiation Sources, the University of Chicago, Chicago, IL 60637, USA.
The New phytologist.New Phytol.2011 Oct;192(1):87-98. doi: 10.1111/j.1469-8137.2011.03789.x. Epub 2011 Jun 10.
? Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. ?
PMID 21658183

Japanese Journal

Transport of DMAA and MMAA into rice (Oryza sativa L.) roots

Azizur Rahman Mohammad,Kadohashi K.,Maki Teruya,Hasegawa Hiroshi
Environmental and Experimental Botany 72(1), 41-46, 2011-08
… Arsenate (As(V)) transport into plant cells has been well studied. …
NAID 120003141555

Transport of DMAA and MMAA into rice (Oryza sativa L.) roots

Rahman M.A.,Kadohashi K.,Maki Teruya,Hasegawa Hiroshi
Environmental and Experimental Botany 72(1), 41-46, 2011-08
… Arsenate (As(V)) transport into plant cells has been well studied. …
NAID 120002086353

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リンク元	「ヒ素」「ヒ酸」「ヒ酸塩」
拡張検索	「arsenate reductase」

「ヒ素」

Arsenate
	IUPAC name arsorate
Identifiers
CAS number	12523-21-6
PubChem	27401
ChemSpider	25498
Jmol-3D images	Image 1
	SMILES [O-][As](=O)([O-])[O-] ;
	InChI InChI=1S/AsH3O4/c2-1(3,4)5/h(H3,2,3,4,5)/p-3; Key: DJHGAFSJWGLOIV-UHFFFAOYSA-K InChI=1/AsH3O4/c2-1(3,4)5/h(H3,2,3,4,5)/p-3; Key: DJHGAFSJWGLOIV-DFZHHIFOAQ ;
Properties
Molecular formula	AsO43-
Molar mass	138.919
	Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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	Infobox references

　　[★]

英: arsenic As
同: 砒素
関: arsenate

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ヒ素 : 約 3,200,000 件
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臨床関連

ヒ素中毒

「ヒ酸」

　　[★]

英: arsenic acid arsenate
関: ヒ酸塩

「ヒ酸塩」

　　[★]

英: arsenate
関: ヒ酸

「arsenate reductase」

　　[★]

ヒ酸還元酵素、ヒ酸レダクターゼ

[1] Mineralienatlas - Mineralklasse Phosphate, Arsenate, Vanadate. (German)

[2] Hughes, Michael F. (2002). "Arsenic toxicity and potential mechanisms of action". Toxicology Letters (133): 4.

[3] Kim Gehle; Selene Chou; William S. Beckett (2009-10-01), Arsenic Toxicity Case Study, Agency for Toxic Substances and Disease Registry

[4] Arsenic-loving bacteria rewrite photosynthesis rules, Chemistry World, 15 August 2008

[5] A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus. Wolfe-Simon F, Blum JS, Kulp TR, Gordon GW, Hoeft SE, Pett-Rdige J, Stolz JF, Webb SM, Weber PK, Davies PCW, Anbar AD, Oremland RS. Science Express. 2 December 2010.

[6] NASA Finds New Arsenic-Based Life Form in California, Wired Science, 2 December 2010

[7] Wolfe-Simon, F., Blum, J.S., Kulp, T.R., Gordon, G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D. & Oremland, R.S. Response to Comments on "A Bacterium That Can Grow Using Arsenic Instead of Phosphorus", Science, 27 May 2011, and references therein. Bibcode 2011Sci...332.1149W. doi:10.1126/science.1202098. Accessed 30 May 2011

[8] Drahl, C. The Arsenic-Based-Life Aftermath. Researchers challenge a sensational claim, while others revisit arsenic biochemistry, Chem Eng News 90(5), 42-47, 30 January 2012. http://cen.acs.org/articles/90/i5/Arsenic-Based-Life-Aftermath.html; accessed 13 October 2012

[9] Science. 8 July 2012. GFAJ-1 Is an Arsenate-Resistant, Phosphate-Dependent Organism. doi: 10.1126/science.1218455. Accessed 10 July 2012.

[10] Science. 8 July 2012. Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells.

[11] ttp://retractionwatch.wordpress.com/2012/07/09/despite-refutation-science-arsenic-life-paper-deserves-retraction-scientist-argues/#comments

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arsenate