Arsenate: Difference between revisions

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(→‎Ions: "In highly acidic conditions it exists as arsenic acid" define "it")
(→‎Bacteria using and generating arsenate: this saga is all disproven)
As with other arsenic compounds, arsenite binds to [[lipoic acid]],<ref>{{Cite web |url= |title=Archived copy |access-date=4 February 2018 |archive-url= |archive-date=20 March 2018 |url-status=dead }}</ref> inhibiting the conversion of [[pyruvate]] into [[acetyl-CoA]], blocking the [[Krebs cycle]] and therefore resulting in further loss of ATP.<ref>{{citation|title=Arsenic Toxicity Case Study|author1=Kim Gehle|author2=Selene Chou|author3=William S. Beckett|publisher=Agency for Toxic Substances and Disease Registry|url=|date=2009-10-01}}</ref>
==Bacteria using and generating arsenate==
{{Main|Arsenate-reducing bacteria}}
Some species of [[bacteria]] obtain their energy by [[redox|oxidizing]] various fuels while [[redox|reducing]] arsenates to form [[arsenite]]s. The [[enzyme]]s involved are known as [[arsenate reductase]]s.
In 2008, bacteria were discovered that employ a version of [[photosynthesis]] with arsenites as [[electron donor]]s, 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.<ref>[ "Arsenic-loving bacteria rewrite photosynthesis rules"], ''Chemistry World'', 15 August 2008</ref>
In 2010, a team at [[NASA]]'s [[NASA Astrobiology Institute|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,<ref>[ "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus"]. 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. ''Science Express''. 2 December 2010.</ref><ref>[ "NASA Finds New Arsenic-Based Life Form in California"], ''Wired Science'', 2 December 2010</ref> However, these claims were immediately debated and critiqued in correspondence to the original journal of publication,<ref>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</ref> and have since come to be widely disbelieved.<ref>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.; accessed 13 October 2012</ref> 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]].<ref>''Science''. 8 July 2012. "GFAJ-1 Is an Arsenate-Resistant, Phosphate-Dependent Organism." doi: 10.1126/science.1218455. Accessed 10 July 2012.</ref><ref>''Science''. 8 July 2012. "Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells."</ref> 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 misrepresentation of critical data.<ref></ref>
==See also==