View source for Adenine

{{Short description|Chemical compound in DNA and RNA}}
{{Distinguish|Adenosine|Adrenaline}}

{{Chembox
| Watchedfields  = changed
| verifiedrevid  = 477242257
| Name           = 
| ImageFile      = 
| ImageFile1     = Adenine numbered.svg
| ImageSize1     = 120px
| ImageClass1 = skin-invert-image
| ImageFileL2    = Adenine-3D-balls.png
| ImageClassL2 = bg-transparent
| ImageFileR2    = Adenine-3D-vdW.png
| ImageClassR2 = bg-transparent
| PIN            = 9''H''-Purin-6-amine
| OtherNames     = 6-Aminopurine
| SystematicName = 
| Section1       = {{Chembox Identifiers
| CASNo = 73-24-5
| CASNo_Ref = {{cascite|correct|CAS}}
| Beilstein = 608603
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 16708
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 226345
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID=185
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB00173
| EINECS = 200-796-1
| Gmelin = 3903
| IUPHAR_ligand = 4788
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D00034
| PubChem = 190
| RTECS = AU6125000
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = JAC85A2161
| InChI = 1/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10)
| InChIKey = GFFGJBXGBJISGV-UHFFFAOYAT
| SMILES = NC1=NC=NC2=C1N=CN2
| SMILES1 = Nc1c2ncNc2ncn1
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = GFFGJBXGBJISGV-UHFFFAOYSA-N
  }}
| Section2       = {{Chembox Properties
| C=5 | H=5 | N=5
| MolarMass = 135.13 g/mol
| Appearance = white to light yellow, crystalline
| Density = 1.6 g/cm<sup>3</sup> (calculated)
| MeltingPtC = 360 to 365
| MeltingPt_notes = decomposes
| BoilingPt =
| Solubility = 0.103 g/100 mL
| SolubleOther = negligible in [[ethanol]], soluble in hot water and/or [[aqua ammonia]]
| pKa=4.15 (secondary), 9.80 (primary)<ref>Dawson, R.M.C., et al., ''Data for Biochemical Research'', Oxford, Clarendon Press, 1959.</ref>
  }}
| Section3       = 
| Section4       = {{Chembox Thermochemistry
| DeltaHf = 96.9 kJ/mol
| HeatCapacity = 147.0 J/(K·mol)
  }}
| Section5       = {{Chembox Hazards
| ExternalSDS = [http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=PL&language=EN-generic&productNumber=A8626&brand=SIGMA&PageToGoToURL=http%3A//www.sigmaaldrich.com/catalog/product/sigma/a8626%3Flang%3Dpl MSDS]
| MainHazards = 
| FlashPtC= 
| AutoignitionPtC =
| LD50 = 227 mg/kg (rat, oral)
  }}
| Section6       = 
}}

'''Adenine'''{{efn|{{IPAc-en|ˈ|æ|d|ᵻ|n|iː|n}}, {{IPAc-en|ˈ|æ|d|ᵻ|n|ᵻ|n}} }} ([[nucleoside#List of nucleosides and corresponding nucleobases|symbol]] '''A,'''<ref>{{Cite encyclopedia |title=A |encyclopedia=Henderson's Dictionary of Biological Terms |last=Lawrence |first=Eleanor |page=1 |isbn=0-470-21446-5}}</ref> or '''Ade''') is a  [[purine]] [[nucleotide base]] that is found in [[DNA]], [[RNA]], and [[Adenosine triphosphate|ATP]].<ref name="Myers">{{Cite book|last=Myers|first=Richard L.|url=https://books.google.com/books?id=0AnJU-hralEC|title=The 100 Most Important Chemical Compounds: A Reference Guide|date=2007|publisher=ABC-CLIO|isbn=978-0-313-33758-1|language=en|pages=13–17|access-date=21 November 2015|archive-date=17 June 2016|archive-url=https://web.archive.org/web/20160617093705/https://books.google.com/books?id=0AnJU-hralEC|url-status=live}}</ref> Usually a white crystalline subtance.<ref name="Myers" /> The shape of adenine is complementary and pairs to either [[thymine]] in DNA or [[uracil]] in RNA.<ref name="Myers" /> In cells adenine, as an independent molecule, is rare. It is almost always [[covalent bond|covalently bound]] to become a part of a larger biomolecule.

Adenine has a central role in [[cellular respiration]]. It is part of [[adenosine triphosphate]] which provides the [[energy]] that drives and supports most activities in living [[cell (biology)|cells]], such as [[Protein biosynthesis|protein synthesis]], [[chemical synthesis]], [[muscle contraction]], and [[nerve impulse]] propagation.<ref>{{cite journal |last1=Dunn |first1=Jacob |last2=Grider |first2=Michael H. |title=Physiology, Adenosine Triphosphate |url=https://www.ncbi.nlm.nih.gov/books/NBK553175/ |website=StatPearls |publisher=StatPearls Publishing |access-date=13 November 2023 |date=2023 |pmid=31985968}}</ref> In respiration it also participates as part of the [[cofactor (biochemistry)|cofactors]] [[nicotinamide adenine dinucleotide]], [[flavin adenine dinucleotide]], and [[Coenzyme A]].

It is also part of [[adenosine]], [[adenosine monophosphate]], [[cyclic adenosine monophosphate]], [[adenosine diphosphate]], and [[S-adenosylmethionine]].

== Structure ==
Adenine forms several [[tautomer]]s, compounds that can be rapidly interconverted and are often considered equivalent. However, in isolated conditions, i.e. in an inert gas matrix and in the gas phase, mainly the 9H-adenine tautomer is found.<ref>{{Cite journal
|journal =Phys. Chem. Chem. Phys.
|year =2002
|volume =4
|issue =20
|pages =4877–4882
|title =Tautomers and electronic states of jet-cooled adenine investigated by double resonance spectroscopy
|author =Plützer, Chr. |author2=Kleinermanns, K.
|bibcode =2002PCCP....4.4877P
|doi =10.1039/b204595h
}}</ref><ref>{{Cite journal
|title = Experimental matrix isolation and theoretical ab initio HF/6-31G(d, p) studies of infrared spectra of purine, adenine and 2-chloroadenine
|journal = Spectrochimica Acta Part A: Molecular Spectroscopy
|volume = 50
|pages = 1081–1094
|year = 1994
|issn = 0584-8539
|doi = 10.1016/0584-8539(94)80030-8
|author1=M. J. Nowak |author2=H. Rostkowska |author3=L. Lapinski |author4=J. S. Kwiatkowski |author5=J. Leszczynski |issue = 6
|bibcode = 1994AcSpA..50.1081N }}</ref>

== Biosynthesis ==
[[Purine metabolism]] involves the formation of adenine and [[guanine]]. Both adenine and guanine are derived from the nucleotide [[inosine monophosphate]] (IMP), which in turn is synthesized from a pre-existing [[ribose phosphate]] through a complex pathway using atoms from the [[amino acid]]s [[glycine]], [[glutamine]], and [[aspartic acid]], as well as the coenzyme [[tetrahydrofolate]].


Patented August 20, 1968, the current recognized method of industrial-scale production of adenine involves heating [[formamide]] under 120 °C.<ref>{{Cite patent|title=Process for preparing adenine|gdate=1966-11-10|url=https://patents.google.com/patent/US3398149A/en}}</ref>

== Function ==
Adenine is one of the two purine [[nucleobase]]s (the other being [[guanine]]) used in forming [[nucleotide]]s of the [[nucleic acid]]s. In DNA, adenine binds to [[thymine]] via two [[hydrogen bond]]s to assist in stabilizing the nucleic acid structures. In RNA, which is used for [[Protein biosynthesis|protein synthesis]], adenine binds to [[uracil]].

{| class="wikitable left" style="text-align:center"
|-
| [[File:Base pair AT.svg|180px|class=skin-invert-image]]
| [[File:Base pair AU.svg|180px|class=skin-invert-image]]
| [[File:Base pair AD.svg|180px|class=skin-invert-image]]
| [[File:Base pair APsi.svg|180px|class=skin-invert-image]]
|-
| A-T-Base-pair (DNA)
| A-U-Base-pair (RNA)
| A-D-Base-pair (RNA)
| A-Ψ-Base-pair (RNA)
|}

Adenine forms [[adenosine]], a [[nucleoside]], when attached to [[ribose]], and [[deoxyadenosine]] when attached to [[deoxyribose]].<ref name="Myers" /> It forms [[adenosine triphosphate]] (ATP), a [[nucleoside triphosphate]], when three [[phosphate group]]s are added to adenosine. Adenosine triphosphate is used in cellular metabolism as one of the basic methods of transferring [[chemical energy]] between [[chemical reactions]].<ref name="Myers" /> ATP is thus a derivative of adenine, [[adenosine]], [[cyclic adenosine monophosphate]], and [[adenosine diphosphate]].

:{| class="wikitable left" style="text-align:center"
|-
| [[File:Adenosin.svg|170px|class=skin-invert-image]]
| [[File:Desoxyadenosin.svg|170px|class=skin-invert-image]]
|-
| Adenosine, A
| Deoxyadenosine, dA
|}

== 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>

== Notes ==
{{notelist}}

== References ==
{{Reflist}}

== External links ==
{{Commons category}}
* [http://gmd.mpimp-golm.mpg.de/Spectrums/f082d045-7938-4e4e-8841-1d748bccc768.aspx Vitamin B4 MS Spectrum]

{{Nucleobases, nucleosides, and nucleotides}}
{{Vitamin}}

{{Authority control}}

[[Category:Nucleobases]]
[[Category:Purines]]
[[Category:Vitamins]]