Adenine

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Adenine
Identifiers
CAS number73-24-5 YesY
PubChem190
ChemSpider185 YesY
UNIIJAC85A2161 YesY
DrugBankDB00173
KEGGD00034 YesY
ChEBICHEBI:16708 YesY
ChEMBLCHEMBL226345 YesY
Jmol-3D imagesImage 1
Image 2
Properties
Molecular formulaC5H5N5
Molar mass135.13 g/mol
Appearancewhite, crystalline
Density1.6 g/cm3 (calculated)
Melting point

360–365 °C (decomposes)

Acidity (pKa)4.15 (secondary), 9.80 (primary)[1]
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
  (Redirected from Vitamin B4)
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Adenine
Identifiers
CAS number73-24-5 YesY
PubChem190
ChemSpider185 YesY
UNIIJAC85A2161 YesY
DrugBankDB00173
KEGGD00034 YesY
ChEBICHEBI:16708 YesY
ChEMBLCHEMBL226345 YesY
Jmol-3D imagesImage 1
Image 2
Properties
Molecular formulaC5H5N5
Molar mass135.13 g/mol
Appearancewhite, crystalline
Density1.6 g/cm3 (calculated)
Melting point

360–365 °C (decomposes)

Acidity (pKa)4.15 (secondary), 9.80 (primary)[1]
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Adenine (A, Ade) is a nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), and protein synthesis, as a chemical component of DNA and RNA.[2] The shape of adenine is complementary to either thymine in DNA or uracil in RNA.

Contents

Structure

Adenine structure, with standard numbering of positions in red.

Adenine forms several tautomers, compounds that can be rapidly interconverted and are often considered equivalent.[citation needed] However, in isolated conditions, i.e. in an inert gas matrix and in the gas phase, mainly the 9H-adenine tautomer is found.[3][4]

Biosynthesis

Purine metabolism involves the formation of adenine and guanine. Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is synthesised on a pre-existing ribose phosphate through a complex pathway using atoms from the amino acids glycine, glutamine, and aspartic acid, as well as fused with the enzyme tetrahydrofolate.

In Saccharomyces cerevisiae (yeast), the adenine pathway converts P-ribosyl-PP into adenine through a seven-step process.

Function

Adenine is one of the two purine nucleobases (the other being guanine) used in forming nucleotides of the nucleic acids. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. In RNA, which is used for protein synthesis, adenine binds to uracil.

Adenine forms adenosine, a nucleoside, when attached to ribose, and deoxyadenosine when attached to deoxyribose. It forms adenosine triphosphate (ATP), a nucleotide, when three phosphate groups are added to adenosine. Adenosine triphosphate is used in cellular metabolism as one of the basic methods of transferring chemical energy between chemical reactions.

History

In older literature, adenine was sometimes called Vitamin B4.[5] It is no longer considered a true vitamin or part of the Vitamin B complex. However, two B vitamins, 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, in reference to the pancreas (a specific gland - in Greek, "aden") from which Kossel's sample had been extracted.[6]

Experiments performed in 1961 by Joan Oró have shown that a large quantity of adenine can be synthesized from the polymerization of ammonia with five hydrogen cyanide (HCN) molecules in aqueous solution;[7] whether this has implications for the origin of life on Earth is under debate.[8]

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.[9][10][11] 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 UV light is much more complicated than previously thought"; these findings have implications for spectroscopic measurements of heterocyclic compounds, according to one report.[12]

References

  1. ^ Dawson, R.M.C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.
  2. ^ Definition of Adenine from the Genetics Home Reference - National Institutes of Health
  3. ^ Plützer, Chr., Kleinermanns, K.; Kleinermanns (2002 waht dah). "Tautomers and electronic states of jet-cooled adenine investigated by double resonance spectroscopy". Phys.Chem.Chem.Phys. 4 (20): 4877–4882. Bibcode 2002PCCP....4.4877P. doi:10.1039/b204595h. 
  4. ^ M. J. Nowak and H. Rostkowska and L. Lapinski and J. S. Kwiatkowski and J. Leszczynski (1994). "Experimental matrix isolation and theoretical ab initio HF/6-31G(d, p) studies of infrared spectra of purine, adenine and 2-chloroadenine,". Spectrochimica Acta Part A: Molecular Spectroscopy 50 (6): 1081–1094. Bibcode 1994AcSpA..50.1081N. doi:10.1016/0584-8539(94)80030-8. ISSN 0584-8539. http://www.sciencedirect.com/science/article/B6THM-44JM8D7-9J/2/36ce6ab26fc6c5aae4a120f9e7bb7d88. 
  5. ^ Vera Reader (1930). "The assay of vitamin B4". Biochem J. 24 (6): 1827–31. PMC 1254803. PMID 16744538. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1254803/. 
  6. ^ Online Etymology Dictionary by Douglas Harper
  7. ^ Oró J, Kimball AP (August 1961). "Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide". Archives of biochemistry and biophysics 94 (2): 217–27. doi:10.1016/0003-9861(61)90033-9. PMID 13731263. 
  8. ^ Shapiro, Robert (June, 1995). "The prebiotic role of adenine: A critical analysis". Origins of Life and Evolution of Biospheres 25 (1–3): 83–98. Bibcode 1995OLEB...25...83S. doi:10.1007/BF01581575. http://www.springerlink.com/content/ru56122875200030/. 
  9. ^ Callahan; Smith, K.E.; Cleaves, H.J.; Ruzica, J.; Stern, J.C.; Glavin, D.P.; House, C.H.; Dworkin, J.P. (11 August 2011). "Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases". PNAS. doi:10.1073/pnas.1106493108. http://www.pnas.org/content/early/2011/08/10/1106493108. Retrieved 2011-08-15. 
  10. ^ Steigerwald, John (8 August 2011). "NASA Researchers: DNA Building Blocks Can Be Made in Space". NASA. http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html. Retrieved 2011-08-10. 
  11. ^ ScienceDaily Staff (9 August 2011). "DNA Building Blocks Can Be Made in Space, NASA Evidence Suggests". ScienceDaily. http://www.sciencedaily.com/releases/2011/08/110808220659.htm. Retrieved 2011-08-09. 
  12. ^ Philip Williams (Aug. 18, 2011). "Physicists Uncover New Data On Adenine, a Crucial Building Block of Life". Science Daily. http://www.sciencedaily.com/releases/2011/08/110818101731.htm. Retrieved 2011-09-01. "journal reference: Mario Barbatti, Susanne Ullrich. Ionization potentials of adenine along the internal conversion pathways. Physical Chemistry Chemical Physics, 2011; doi:10.1039/C1CP21350D -- a University of Georgia physicist and a collaborator in Germany have shown that ... adenine, has an unexpectedly variable range of ionization energies along its reaction pathways...."