Editing Coenzyme Q10 (section)

==Biochemistry==
{{Expert needed|biochemistry|talk=Biological function|date=April 2024}}
Coenzymes Q is a [[cofactor (biochemistry)|coenzyme]] family that is [[ubiquitous]] in animals and many [[Pseudomonadota]],<ref name="pmid20599680">{{cite journal | vauthors = Nowicka B, Kruk J | title = Occurrence, biosynthesis and function of isoprenoid quinones | journal = Biochimica et Biophysica Acta (BBA) - Bioenergetics | volume = 1797 | issue = 9 | pages = 1587–1605 | date = September 2010 | pmid = 20599680 | doi = 10.1016/j.bbabio.2010.06.007 | doi-access = free }}</ref> a group of gram-negative bacteria. The fact that the coenzyme is ubiquitous gives the origin of its other name, ubiquinone.<ref name=lpi/><ref name=sood/><ref name="pubchem-Ubidecarenone">{{Include-USGov|agency=[[National Center for Biotechnology Information]]|title=Ubidecarenone |url=https://pubchem.ncbi.nlm.nih.gov/compound/5281915 | work = PubChem | publisher = US National Library of Medicine |access-date=4 April 2024 |date=30 March 2024}}</ref> In humans, the most common form of coenzymes Q is coenzyme Q<sub>10</sub>, also called CoQ<sub>10</sub> ({{IPAc-en|ˌ|k|oʊ|k|j|uː|ˈ|t|ɛ|n}}) or ubiquinone-10.<ref name=lpi/>

Coenzyme Q<sub>10</sub> is a [[1,4-Benzoquinone|1,4-benzoquinone]], in which "Q" refers to the [[quinone]] chemical group and "10" refers to the number of [[isoprene|isoprenyl]] chemical subunits (shown enclosed in brackets in the diagram) in its tail.<ref name=lpi/> In natural ubiquinones, there are from six to ten subunits in the tail, with humans having a tail of 10 isoprene units (50 carbon atoms) connected to its benzoquinone "head".<ref name=lpi/>

This family of fat-soluble substances is present in all respiring [[Eukaryote|eukaryotic]] cells, primarily in the mitochondria.<ref name=lpi/> Ninety-five percent of the human body's energy is generated this way.<ref name="pmid7599208">{{cite journal | vauthors = Ernster L, Dallner G | title = Biochemical, physiological and medical aspects of ubiquinone function | journal = Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease | volume = 1271 | issue = 1 | pages = 195–204 | date = May 1995 | pmid = 7599208 | doi = 10.1016/0925-4439(95)00028-3 | doi-access = free }}</ref> Organs with the highest energy requirements—such as the [[heart]], [[liver]], and [[kidney]]—have the highest CoQ<sub>10</sub> concentrations.<ref name="pmid2599795">{{cite journal | vauthors = Okamoto T, Matsuya T, Fukunaga Y, Kishi T, Yamagami T | title = Human serum ubiquinol-10 levels and relationship to serum lipids | journal = International Journal for Vitamin and Nutrition Research | volume = 59 | issue = 3 | pages = 288–292 | year = 1989 | pmid = 2599795 }}</ref><ref name="pmid1586151">{{cite journal | vauthors = Aberg F, Appelkvist EL, Dallner G, Ernster L | title = Distribution and redox state of ubiquinones in rat and human tissues | journal = Archives of Biochemistry and Biophysics | volume = 295 | issue = 2 | pages = 230–234 | date = June 1992 | pmid = 1586151 | doi = 10.1016/0003-9861(92)90511-T }}</ref><ref name="pmid8288904">{{cite journal | vauthors = Shindo Y, Witt E, Han D, Epstein W, Packer L | title = Enzymic and non-enzymic antioxidants in epidermis and dermis of human skin | journal = The Journal of Investigative Dermatology | volume = 102 | issue = 1 | pages = 122–124 | date = January 1994 | pmid = 8288904 | doi = 10.1111/1523-1747.ep12371744 | doi-access =  }}</ref><ref name="Žmitek-2008">{{cite journal|vauthors=Žmitek J, ŽMitek K, Pravs I|title=Improving the bioavailability of coenzyme q10 from theory to practice|year=2008|journal=Agro Food Industry Hi-Tech|url=https://www.scopus.com/inward/record.uri?eid=2-s2.0-53849139131&partnerID=40&md5=25ac2ff16eec9fc4a8b52430316bfbd8|access-date=5 April 2024|archive-date=23 April 2024|archive-url=https://web.archive.org/web/20240423075336/https://www.scopus.com/record/display.uri?eid=2-s2.0-53849139131&origin=inward&txGid=4f4a035686dfee6b6fbde3099b06b518|url-status=live}}</ref>

There are three [[redox]] states of CoQ: fully oxidized (''ubi''quinone), [[Semiquinone|''semi''quinone]] (''ubisemi''quinone), and fully [[Organic redox reaction|reduced]] ([[ubiquinol]]).<ref name=lpi/> The capacity of this molecule to act as a two-electron carrier (moving between the quinone and quinol form) and a one-electron carrier (moving between the semiquinone and one of these other forms) is central to its role in the electron transport chain due to the [[iron–sulfur cluster]]s that can only accept one electron at a time and as a free radical–scavenging antioxidant.<ref name=lpi/><ref name="pubchem-Ubidecarenone"/>