Adenine

Adenine.svg
Adenine-3D-balls.png
Adenine-3D-vdW.png
Names
Preferred IUPAC name
9H-Purin-6-amine
Other names
6-Aminopurine
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard100.000.724 Edit this at Wikidata
EC Number
  • 200-796-1
IUPHAR/BPS
KEGG
PubChem CID
RTECS number
  • AU6125000
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10) checkY
    Key: GFFGJBXGBJISGV-UHFFFAOYSA-N checkY
  • InChI=1/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10)
    Key: GFFGJBXGBJISGV-UHFFFAOYAT
SMILES
  • NC1=NC=NC2=C1N=CN2
  • Nc1c2ncNc2ncn1
Properties
Chemical formula
C5H5N5
Molar mass135.13 g/mol
Appearancewhite to light yellow, crystalline
Density1.6 g/cm3 (calculated)
Melting point 360 to 365 °C (680 to 689 °F; 633 to 638 K) decomposes
Solubility in water
0.103 g/100 mL
Solubilitynegligible in ethanol, soluble in hot water and/or aqua ammonia
Acidity (pKa)4.15 (secondary), 9.80 (primary)[1]
Thermochemistry
Heat capacity (C)
147.0 J/(K·mol)
Std enthalpy of
formation
fH298)
96.9 kJ/mol
Hazards
Safety data sheetMSDS
Lethal dose or concentration (LD, LC):
LD50 (median dose)
227 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Infobox references

Adenine (/ˈædɪnɪn/) (symbol A or Ade) is a nucleobase (a purine derivative). It is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The three others are guanine, cytosine and thymine. Its derivatives have 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), flavin adenine dinucleotide (FAD) and Coenzyme A. It also has functions in protein synthesis and as a chemical component of DNA and RNA.[2] The shape of adenine is complementary to either thymine in DNA or uracil in RNA.

The adjacent image shows pure adenine, as an independent molecule. When connected into DNA, a covalent bond is formed between deoxyribose sugar and the bottom left nitrogen (thereby removing the existing hydrogen atom). The remaining structure is called an adenine residue, as part of a larger molecule. Adenosine is adenine reacted with ribose, as used in RNA and ATP; deoxyadenosine is adenine attached to deoxyribose, as used to form DNA.

Structure

(c) Pepemonbu, CC BY-SA 3.0
Adenine structure, with standard numbering of positions in red.

Adenine forms several tautomers, 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.[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 in turn is synthesized from a pre-existing ribose phosphate through a complex pathway using atoms from the amino acids glycine, glutamine, and aspartic acid, as well as the coenzyme tetrahydrofolate.

Manufacturing method

Patented Aug. 20, 1968, the current recognized method of industrial-scale production of adenine is a modified form of the formamide method. This method heats up formamide under 120 degree Celsius conditions within a sealed flask for 5 hours to form adenine. The reaction is heavily increased  in quantity by using a phosphorus oxychloride (phosphoryl chloride) or phosphorus pentachloride as an acid catalyst and sunlight or ultraviolet conditions. After the 5 hours have passed and the formamide-phosphorus oxychloride-adenine solution cools down, water is put into the flask containing the formamide and now-formed adenine. The water-formamide-adenine solution is then poured through a filtering column of activated charcoal. The water and formamide molecules, being small molecules, will pass through the charcoal and into the waste flask; the large adenine molecules, however, will attach or “adsorb” to the charcoal due to the van der waals forces that interact between the adenine and the carbon in the charcoal. Because charcoal has a large surface area, it's able to capture the majority of molecules that pass a certain size (greater than water and formamide) through it. To extract the adenine from the charcoal-adsorbed adenine, ammonia gas dissolved in water (aqua ammonia) is poured onto the activated charcoal-adenine structure to liberate the adenine into the ammonia-water solution. The solution containing water, ammonia, and adenine is then left to air dry, with the adenine losing solubility due to the loss of ammonia gas that previously made the solution basic and capable of dissolving adenine, thus causing it to crystalize into a pure white powder that can be stored. [5]

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.

Base pair AT.svgBase pair AU.svgBase pair AD.svgBase pair APsi.svg
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. It forms adenosine triphosphate (ATP), a nucleoside triphosphate, 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.

Adenosin.svgDesoxyadenosin.svg
Adenosine, ADeoxyadenosine, dA

History

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 B4.[6] 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 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, ἀδήν "aden") from which Kossel's sample had been extracted.[7][8]

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;[9] whether this has implications for the origin of life on Earth is under debate.[10]

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.[11][12][13] 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.[14]

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. (2002). "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; H. Rostkowska; L. Lapinski; J. S. Kwiatkowski; 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.
  5. ^ [1], "Process for preparing adenine", issued 1966-11-10 
  6. ^ Reader V (1930). "The assay of vitamin B(4)". The Biochemical Journal. 24 (6): 1827–31. doi:10.1042/bj0241827. PMC 1254803. PMID 16744538.
  7. ^ A. Kossel (1885) "Ueber eine neue Base aus dem Thierkörper" (On a new base from the animal body), Berichte der Deutschen Chemischen Gesellschaft zu Berlin, 18 : 79-81. From p. 79: "Diese Base, für welche ich den Namen Adenin vorschlage, wurde zunächst aus Pankreasdrüsen vom Rind dargestellt." (This base, for which I suggest the name "adenine", was first prepared from the pancreas glands of steer.)
  8. ^ Online Etymology Dictionary by Douglas Harper
  9. ^ Oro 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.
  10. ^ 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. PMID 11536683. S2CID 21941930.
  11. ^ Callahan MP, Smith KE, Cleaves HJ, Ruzicka J, Stern JC, Glavin DP, House CH, Dworkin JP (Aug 2011). "Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases". Proceedings of the National Academy of Sciences of the United States of America. 108 (34): 13995–8. Bibcode:2011PNAS..10813995C. doi:10.1073/pnas.1106493108. PMC 3161613. PMID 21836052.
  12. ^ Steigerwald, John (8 August 2011). "NASA Researchers: DNA Building Blocks Can Be Made in Space". NASA. Retrieved 2011-08-10.
  13. ^ ScienceDaily Staff (9 August 2011). "DNA Building Blocks Can Be Made in Space, NASA Evidence Suggests". ScienceDaily. Retrieved 2011-08-09.
  14. ^ Williams P (August 18, 2011). "Physicists Uncover New Data On Adenine, a Crucial Building Block of Life". Science Daily. 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....

External links

Media files used on this page

Base pair AT.svg
Base pair Adenine Tyhmine (AT)
Base pair AD.svg
Structure of base pair Adenine Dihydrouracil (AD)
Base pair APsi.svg
base pair Adenine Pseudouridine (AΨ)
Adenine-3D-vdW.png
3D vdW - Adenine
Adenosin.svg
Structure of adenosine
Template from Crick and Watson’s DNA molecular model, 1953. (9660573227).jpg
Author/Creator: Science Museum, London / Science and Society Picture Library, Licence: CC BY-SA 2.0
This aluminium template representing the base thymine (T) is part of Crick and Watson’s model of DNA. Bases are those groups of atoms that make up DNA's twin strands. The bases in each of the strands combines to spell out the organism's genetic code. This structure of DNA was discovered by Francis Crick (b 1916) and James Dewey Watson (b 1928) whilst working in the Medical Research Council Unit at the Cavendish Laboratory in Cambridge and after having seen X-ray diffraction pattern photographs of DNA by Rosalind Franklin. In 1953 Watson and Crick constructed a molecular model of the complex genetic material deoxyribonucleic acid (DNA). Their analysis of the double helix shape of DNA explained how genetic information could be copied and passed from one generation to the next. They were awarded the Nobel Prize for medicine and physiology in 1962.
Adenine-3D-balls.png
3D balls - Adenine
Base pair AU.svg
base pair Adenine Uracil (AU)
Desoxyadenosin.svg
Structure of Deoxyadenosine
Adenine numbered.svg
(c) Pepemonbu, CC BY-SA 3.0
Adenine, with standard numbering of positions.
Adenine.svg
Author/Creator: Pepemonbu, Licence: CC-BY-SA-3.0
Chemical Structure of Adenine in vector format