Editing Copper (section)

=== Biochemistry ===
[[Copper proteins]] have diverse roles in biological electron transport and oxygen transportation, processes that exploit the easy interconversion of Cu(I) and Cu(II).<!-- this obscure detail probably doesn't need so many citations, someone read on the topic should choose one and remove the rest !--><ref>{{cite book
|first1=Katherine E. |last1=Vest|first2=Hayaa F.|last2=Hashemi|first3=Paul A.|last3=Cobine
|chapter=The Copper Metallome in Eukaryotic Cells |editor1-first=Lucia |editor1-last=Banci |series=Metal Ions in Life Sciences |volume=12
|title=Metallomics and the Cell |date=2013 |pages=451–78|publisher=Springer |isbn=978-94-007-5560-4|doi=10.1007/978-94-007-5561-1_13|pmid=23595680}} electronic-book {{ISBN|978-94-007-5561-1}} {{ISSN|1559-0836}} electronic-{{ISSN|1868-0402}}
</ref> Copper is essential in the aerobic [[Cellular respiration|respiration]] of all [[eukaryotes]]. In [[mitochondria]], it is found in [[cytochrome c oxidase]], which is the last protein in [[oxidative phosphorylation]]. Cytochrome c oxidase is the protein that binds the O<sub>2</sub> between a copper and an iron; the protein transfers 4 electrons to the O<sub>2</sub> molecule to reduce it to two molecules of water. Copper is also found in many [[superoxide dismutase]]s, proteins that catalyze the decomposition of [[superoxide]]s by converting it (by [[disproportionation]]) to oxygen and [[hydrogen peroxide]]:
* Cu<sup>2+</sup>-SOD + O<sub>2</sub><sup>−</sup> → Cu<sup>+</sup>-SOD + O<sub>2</sub> (reduction of copper; oxidation of superoxide)
* Cu<sup>+</sup>-SOD + O<sub>2</sub><sup>−</sup> + 2H<sup>+</sup> → Cu<sup>2+</sup>-SOD + H<sub>2</sub>O<sub>2</sub> (oxidation of copper; reduction of superoxide)

The protein [[hemocyanin]] is the oxygen carrier in most [[mollusk]]s and some [[arthropod]]s such as the [[horseshoe crab]] (''Limulus polyphemus'').<ref name="NOAA">{{cite web|title = Fun facts|work = Horseshoe crab|publisher = University of Delaware|url = http://www.ocean.udel.edu/horseshoecrab/funFacts.html|access-date = 13 July 2008|archive-url = https://web.archive.org/web/20081022053340/http://www.ocean.udel.edu/horseshoecrab/funFacts.html|archive-date = 22 October 2008|url-status = dead}}</ref> Because hemocyanin is blue, these organisms have blue blood rather than the red blood of iron-based [[hemoglobin]]. Structurally related to hemocyanin are the [[laccase]]s and [[tyrosinase]]s. Instead of reversibly binding oxygen, these proteins hydroxylate substrates, illustrated by their role in the formation of [[lacquer]]s.<ref name="Lippard">S.J. Lippard, J.M. Berg "Principles of bioinorganic chemistry" University Science Books: Mill Valley, CA; 1994. {{ISBN|0-935702-73-3}}.</ref> The biological role for copper commenced with the appearance of oxygen in Earth's atmosphere.<ref>{{cite journal|pmid=10821735|author=Decker, H.|author2=Terwilliger, N.|name-list-style=amp |title=COPs and Robbers: Putative evolution of copper oxygen-binding proteins|journal= Journal of Experimental Biology |volume=203|pages=1777–1782 |date=2000|issue=Pt 12|doi=10.1242/jeb.203.12.1777|doi-access=free|bibcode=2000JExpB.203.1777D }}</ref> Several copper proteins, such as the "blue copper proteins", do not interact directly with substrates; hence they are not enzymes. These proteins relay electrons by the process called [[electron transfer]].<ref name="Lippard" />
[[File:Thylakoid membrane.png|thumb|upright=2|Photosynthesis functions by an elaborate electron transport chain within the [[thylakoid membrane]]. A central link in this chain is [[plastocyanin]], a blue copper protein.]]

A unique tetranuclear copper center has been found in [[nitrous-oxide reductase]].<ref>
{{cite book
|first1=Lisa K.
|last1= Schneider
|first2=Anja
|last2= Wüst
|first3=Anja
|last3= Pomowski
|first4=Lin
|last4= Zhang
|first5=Oliver
|last5= Einsle
|chapter= No Laughing Matter: The Unmaking of the Greenhouse Gas Dinitrogen Monoxide by Nitrous Oxide Reductase
|editor=Peter M.H. Kroneck
|editor2=Martha E. Sosa Torres
|title=The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment
|series=Metal Ions in Life Sciences
|volume=14
|date=2014
|publisher=Springer
|pages=177–210
|doi=10.1007/978-94-017-9269-1_8
|pmid= 25416395
|isbn= 978-94-017-9268-4
}}
</ref>

Chemical compounds which were developed for treatment of Wilson's disease have been investigated for use in cancer therapy.<ref>{{cite book|last1=Denoyer|first1=Delphine| last2=Clatworthy |first2=Sharnel A.S.| last3=Cater |first3=Michael A. |editor1-last=Sigel|editor1-first=Astrid|editor2-last=Sigel|editor2-first=Helmut|editor3-last=Freisinger|editor3-first=Eva|editor4-last=Sigel|editor4-first=Roland K.O.
|title=Metallo-Drugs: Development and Action of Anticancer Agents|date=2018|volume= 18|doi= 10.1515/9783110470734-016
|pmid=29394035|publisher=de Gruyter GmbH|location=Berlin|chapter= Chapter 16. Copper Complexes in Cancer Therapy|journal=Metal Ions in Life Sciences |pages= 469–506|isbn=978-3-11-047073-4}}</ref>