Editing Adenine (section)

== History ==
[[File:Template from Crick and Watson’s DNA molecular model, 1953. (9660573227).jpg|thumb|Adenine on Crick and Watson's DNA molecular model, 1953. The picture is shown upside down compared to most modern drawings of adenine, such as those used in this article.]]
In older literature, adenine was sometimes called '''Vitamin B<sub>4</sub>''', but is no longer considered a vitamin.<ref>{{Cite journal | vauthors = Reader V | title = The assay of vitamin B(4) | journal = The Biochemical Journal | volume = 24 | issue = 6 | pages = 1827–31 | year = 1930 | pmid = 16744538 | pmc = 1254803 | doi=10.1042/bj0241827}}</ref><ref name="Myers" /> Due to it being synthesized by the body and not essential to be obtained by diet, it does not meet the definition of [[vitamin]] and is no longer part of the [[Vitamin B]] complex. However, two B vitamins, [[Niacin (substance)|niacin]] and [[riboflavin]], bind with adenine to form the essential cofactors [[nicotinamide adenine dinucleotide]] (NAD) and [[flavin adenine dinucleotide]] (FAD), respectively. [[Hermann Emil Fischer]] was one of the early scientists to study adenine.

It was named in 1885 by [[Albrecht Kossel]] after [[Greek language|Greek]] ''ἀδήν'' aden "gland", in reference to the pancreas, from which Kossel's sample had been extracted.<ref>{{Cite web|last=texte|first=Deutsche chemische Gesellschaft Auteur du|date=1885-01-01|title=Berichte der Deutschen chemischen Gesellschaft zu Berlin|url=https://gallica.bnf.fr/ark:/12148/bpt6k90702f|access-date=2022-12-23|website=Gallica|language=EN}}</ref><ref>{{Cite web|title=adenine &#124; Etymology, origin and meaning of adenine by etymonline|url=https://www.etymonline.com/word/adenine|access-date=2022-12-23|website=www.etymonline.com|language=en}}</ref>

Adenine can be prepared from [[ammonia]] and [[hydrogen cyanide]] (HCN) in aqueous solution,<ref>{{Cite journal | vauthors = Oro J, Kimball AP | title = Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide | journal = Archives of Biochemistry and Biophysics | volume = 94 | issue = 2 | pages = 217–27 | date = August 1961 | pmid = 13731263 | doi = 10.1016/0003-9861(61)90033-9 }}</ref> a process that has implications for the [[origin of life]] on [[Earth]].<ref>{{Cite journal
|title =The prebiotic role of adenine: A critical analysis
|first =Robert
|last =Shapiro
|journal =Origins of Life and Evolution of Biospheres
|date =June 1995
|doi =10.1007/BF01581575
|pmid =11536683
|pages =83–98
|volume =25
|issue =1–3
|bibcode = 1995OLEB...25...83S |s2cid =21941930
}}</ref>

On August 8, 2011, a report, based on [[NASA]] studies with [[meteorites]] found on [[Earth]], was published suggesting building blocks of [[DNA]] and [[RNA]] (adenine, [[guanine]] and related [[organic molecules]]) may have been formed extraterrestrially in [[outer space]].<ref name="Callahan">{{Cite journal | vauthors = Callahan MP, Smith KE, Cleaves HJ, Ruzicka J, Stern JC, Glavin DP, House CH, Dworkin JP | title = Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 108 | issue = 34 | pages = 13995–8 | date = Aug 2011 | pmid = 21836052 | doi = 10.1073/pnas.1106493108 | pmc=3161613| bibcode = 2011PNAS..10813995C | doi-access = free }}</ref><ref name="Steigerwald">{{Cite web |last=Steigerwald |first=John |title=NASA Researchers: DNA Building Blocks Can Be Made in Space |url=http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html |publisher=[[NASA]] |date=8 August 2011 |access-date=2011-08-10 |archive-date=2015-06-23 |archive-url=https://web.archive.org/web/20150623004556/http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html |url-status=dead }}</ref><ref name="DNA">{{Cite web |author =ScienceDaily Staff |title=DNA Building Blocks Can Be Made in Space, NASA Evidence Suggests|url=https://www.sciencedaily.com/releases/2011/08/110808220659.htm |date=9 August 2011 |website=[[ScienceDaily]] |access-date=2011-08-09}}</ref> In 2011, physicists reported that adenine has an "unexpectedly variable range of ionization energies along its reaction pathways" which suggested that "understanding experimental data on how adenine survives exposure to [[ultraviolet light|UV light]] is much more complicated than previously thought"; these findings have implications for [[spectroscopy|spectroscopic]] measurements of [[heterocyclic]] compounds, according to one report.<ref name=twsA35>{{Cite web  | first1 = Philip | last1 = Williams | name-list-style = vanc | title= Physicists Uncover New Data On Adenine, a Crucial Building Block of Life | website= Science Daily | date = August 18, 2011 | url = https://www.sciencedaily.com/releases/2011/08/110818101731.htm | access-date = 2011-09-01}}
*{{Cite journal |vauthors=[[Mario Barbatti|Barbatti M]], Ullrich S |title=Ionization potentials of adenine along the internal conversion pathways |journal=Physical Chemistry Chemical Physics |date=2011 |volume=13 |issue=34 |pages=15492–15900 |doi=10.1039/C1CP21350D|pmid=21804965 |bibcode=2011PCCP...1315492B }}</ref>