View source for Hypoxanthine

{{chembox
| verifiedrevid = 443865679
| ImageFile=Hypoxanthin.svg
| ImageSize=
| PIN=1,9-Dihydro-6''H''-purin-6-one
| OtherNames=
|Section1={{Chembox Identifiers
| IUPHAR_ligand = 4555
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 768
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 2TN51YD919
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C00262
| InChI = 1/C5H4N4O/c10-5-3-4(7-1-6-3)8-2-9-5/h1-2H,(H2,6,7,8,9,10)
| InChIKey = FDGQSTZJBFJUBT-UHFFFAOYAJ
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 1427
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C5H4N4O/c10-5-3-4(7-1-6-3)8-2-9-5/h1-2H,(H2,6,7,8,9,10)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = FDGQSTZJBFJUBT-UHFFFAOYSA-N
| CASNo=68-94-0
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem=790
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 17368
| SMILES = c1[nH]c2c(n1)[nH]cnc2=O
| MeSHName=Hypoxanthine
  }}
|Section2={{Chembox Properties
| Formula=C<sub>5</sub>H<sub>4</sub>N<sub>4</sub>O
| MolarMass=136.112
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
  }}
|Section3={{Chembox Hazards
| MainHazards=
| FlashPt=
| AutoignitionPt =
  }}
}}
'''Hypoxanthine''' is a naturally occurring [[purine]] derivative. It is occasionally found as a constituent of [[nucleic acid]]s, where it is present in the [[anticodon]] of [[tRNA]] in the form of its nucleoside [[inosine]]. It has a [[tautomer]] known as 6-hydroxypurine. Hypoxanthine is a necessary additive in certain cells, bacteria, and parasite cultures as a substrate and nitrogen source. For example,<ref>{{cite web |title=Estimation of ''Plasmodium falciparum'' drug susceptibility by the <sup>3</sup>H-hypoxanthine uptake inhibition assay
 |url=http://www.wwarn.org/sites/default/files/attachments/procedures/inv07-estimation-of-plasmodium-falciparum-drug-susceptibility-by-3h-hypoxanthine-uptake-inbition-assay.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.wwarn.org/sites/default/files/attachments/procedures/inv07-estimation-of-plasmodium-falciparum-drug-susceptibility-by-3h-hypoxanthine-uptake-inbition-assay.pdf |archive-date=2022-10-09 |url-status=live |publisher=Worldwide Antimalarial Resistance Network |access-date=2017-01-20}}</ref><ref>{{cite journal|last1=Brockman|first1=A.|last2=Price|first2=R.N.|last3=van Vugt|first3=M.|last4=Heppner|first4=D.G.|last5=Walsh|first5=D.|last6=Sookto|first6=P.|last7=Wimonwattrawatee|first7=T.|last8=Looareesuwan|first8=S.|last9=White|first9=N.J.|last10=Nosten|first10=F.|title=Plasmodium falciparum antimalarial drug susceptibility on the north-western border of Thailand during five years of extensive use of artesunate-mefloquine|journal=Transactions of the Royal Society of Tropical Medicine and Hygiene|date=September 2000|volume=94|issue=5|pages=537–544|doi=10.1016/S0035-9203(00)90080-4|pmid=11132385|pmc=4340572}}</ref> it is commonly a required [[reagent]] in [[malaria culture|malaria parasite cultures]], since ''[[Plasmodium falciparum]]'' requires a source of hypoxanthine for nucleic acid synthesis and energy metabolism.

In August 2011, a report, based on [[NASA]] studies with [[meteorite]]s found on Earth, was published suggesting hypoxanthine and related [[organic molecules]], including the [[DNA]] and [[RNA]] components [[adenine]] and [[guanine]], may have been formed extraterrestrially in outer space.<ref name="Callahan">{{cite journal |last1=Callahan |last2=Smith |first2=K.E. |last3=Cleaves |first3=H.J. |last4=Ruzica |first4=J. |last5=Stern |first5=J.C. |last6=Glavin |first6=D.P. |last7=House |first7=C.H. |last8=Dworkin |first8=J.P. |date=11 August 2011 |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=13995–13998 |doi=10.1073/pnas.1106493108 |pmc=3161613 |pmid=21836052 |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>

The ''[[Pheretima|Pheretima aspergillum]]'' worm, used in Chinese medicine preparations, contains hypoxanthine.<ref>The Pharmacology of Chinese Herbs, Second Edition  By Kee C. Huang</ref>

==Reactions==
It is one of the products of the action of [[xanthine oxidase]] on [[xanthine]].  However, more frequently in [[purine degradation]], xanthine is formed from oxidation of hypoxanthine by [[xanthine oxidoreductase]].

[[Hypoxanthine-guanine phosphoribosyltransferase]] converts hypoxanthine into [[Inosine monophosphate|IMP]] in [[nucleotide salvage]].

Hypoxanthine is also a spontaneous [[deamination]] product of [[adenine]].  Because of its resemblance to [[guanine]], the spontaneous deamination of adenine can lead to an error in [[DNA transcription]]/replication, as it base pairs with [[cytosine]]. Hypoxanthine is removed from DNA by base excision repair, initiated by N-methylpurine glycosylase (MPG), also known as alkyl adenine glycosylase (Aag).<ref>{{cite journal |last1=Lee |first1=Chun-Yue |title=Recognition and Processing of a New Repertoire of DNA Substrates by Human 3-Methyladenine DNA Glycosylase (AAG) |journal=Biochemistry |date=2009 |volume=10 |issue=9 |pages=1850–1861 |doi=10.1021/bi8018898|pmc=2883313 |pmid=19219989}}</ref>

==Additional images==
<gallery>
 Image:Adenin.svg|[[Adenine]]
 Image:Guanin.svg|[[Guanine]]
 Image:Xanthin.svg|[[Xanthine]]
</gallery>

==References==
{{reflist}}

==External links==
* {{MeshName|Hypoxanthine}}

{{Nucleobases, nucleosides, and nucleotides}}
{{Nucleotide metabolism intermediates}}
{{Purinergics}}

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