purine

Information about purine

Purine
IUPAC name7H-purine
Identifiers
CAS number120-73-0
PubChem1044
MeSHPurine
SMILESC1=C2C(=NC=N1)N=CN2
Properties
Molecular formulaC5H4N4
Molar mass120.112
Melting point 214 °C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 C, 100 kPa)
Purine (1) is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines make up one of the two groups of nitrogenous bases. Pyrimidines make up the other group. These bases make up a crucial part of both deoxyribonucleotides and ribonucleotides, and the basis for the universal genetic code.

The general term purines also refers to substituted purines and their tautomers.

The purine is the most widely distributed nitrogen-containing heterocycle in nature.[1]

Notable purines

The quantity of naturally occurring purines produced on earth is enormous, as 50 % of the bases in nucleic acids, adenine (2) and guanine (3), are purines. In DNA, these bases form hydrogen bonds with their complementary pyrimidines thymine and cytosine. This is called complementary base pairing. In RNA, the complement of adenine is uracil (U) instead of thymine.

Other notable purines are hypoxanthine (4), xanthine (5), theobromine (6), caffeine (7), uric acid (8) and isoguanine (9).

Functions

Aside from DNA and RNA, purines are biochemically significant components in a number of other important biomolecules, such as ATP, GTP, cyclic AMP, NADH, and coenzyme A. Purine (1) itself, has not been found in nature, but it can be produced by organic synthesis.

History

The name 'purine' (purum uricum) was coined by the German chemist Emil Fischer in 1884. He synthesized it for the first time in 1899.[2] The starting material for the reaction sequence was uric acid (8), which had been isolated from gallstones by Scheele in 1776.[3] Uric acid (8) was reacted with PCl5 to give 2,6,8-trichloropurine (10), which was converted with HI and PH4I to give 2,6-diiodopurine (11). This latter product was reduced to purine (1) using zinc-dust.

Metabolism

Main article: Purine metabolism
Many organisms have metabolic pathways to synthesize and break down purines.

Purines are biologically synthesized as nucleosides (bases attached to ribose).

Food Sources

Purines are found in high concentration in meat and meat products, especially internal organs such as liver and kidney. Plant based diet is generally low in purines [1].

Examples of high purine sources include: sweetbreads, anchovies, sardines, liver, beef kidneys, brains, meat extracts (e.g Oxo, Bovril), herring, mackerel, scallops, game meats, and gravy.

A moderate amount of purine is also contained in beef, pork, poultry, fish and seafood, asparagus, cauliflower, spinach, mushrooms, green peas, lentils, dried peas, beans, oatmeal, wheat bran and wheat germ.[4]

Moderate intake of purine-containing food is not associated with an increased risk of gout.[5]

Synthesis

Purine (1) is obtained in good yield when formamide is heated in an open vessel at 170 oC for 28 hours.[6]



Procedure:[6] Formamide (45 gram) was heated in an open vessel with a condenser for 28 hours in an oil bath at 170-190 oC. After removing excess formamide (32.1 gram) by vacuum distillation, the residue was refluxed with methanol. The methanol solvent was filtered, the solvent removed from the filtrate by vacuum distillation, and almost pure purine obtained; yield 4.93 gram (71 % yield from formamide consumed). Crystallization from acetone afforded purine as colorless crystals; melting point 218 oC.

Oro, Orgel and co-workers have shown that four molecules of HCN tetramerize to form diaminomaleodinitrile (12), which can be converted into almost all important natural occurring purines.[8][9][10][11][12]

References

1. ^ Rosemeyer, H. Chemistry & Biodiversity 2004, 1, 361.
2. ^ Fischer, E. Berichte der Deutschen Chemischen Gesellschaft 1899, 32, 2550.
3. ^ Scheele, V. Q. Examen Chemicum Calculi Urinari, Opuscula, 1776, 2, 73.
4. ^ [2]
5. ^ [3]
6. ^ Yamada, H.; Okamoto, T. Chemical & Pharmaceutical Bulletin, 1972, 20, 623.
7. ^
8. ^ Sanchez, R. A.; Ferris, J. P.; Orgel, L. E. Journal of Molecular Biology, 1967, 30, 223.
9. ^ Ferris, J. P.; Orgel, L. E. Journal of the American Chemical Society, 1966, 88, 1074.
10. ^ Ferris, J. P.; Kuder, J. E.; Catalano, O. W. Science, 1969, 166, 765.
11. ^ Oro, J.; Kamat, J. S. Nature, 1961, 190, 442.
12. ^ Houben-Weyl, Vol . E5, p. 1547

See also

External links


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Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids:Types of Nucleic AcidsAnalogues of nucleic acids:
Nucleobases: Purine (Adenine, Guanine) | Pyrimidine (Uracil, Thymine, Cytosine)
Nucleosides: Adenosine/Deoxyadenosine | Guanosine/Deoxyguanosine | Uridine | Thymidine | Cytidine/Deoxycytidine
Nucleotides: monophosphates (AMP, UMP, GMP, CMP) | diphosphates (ADP, UDP, GDP, CDP) | triphosphates (ATP, UTP, GTP, CTP) | cyclic (cAMP, cGMP, cADPR)
Deoxynucleotides: monophosphates (dAMP, TMP, dGMP, dCMP) | diphosphates (dADP, TDP, dGDP, dCDP) | triphosphates (dATP, TTP, dGTP, dCTP)
Ribonucleic acids: RNA | mRNA | piRNA | tRNA | rRNA | ncRNA | gRNA | shRNA | siRNA | snRNA | miRNA | snoRNA
Deoxyribonucleic acids: DNA | mtDNA | cDNA | plasmid | Cosmid | BAC | YAC | HAC
Analogues of nucleic acids: GNA | PNA | TNA | Morpholino | LNA
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Molar mass, symbol M,[1] is the mass of one mole of a substance (chemical element or chemical compound).[2] It is a physical property which is characteristic of each pure substance.
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standard state of a material is its state at 1 bar (100 kilopascals exactly). This pressure was changed from 1 atm (101.325 kilopascals) by IUPAC in 1990.[1] The standard state of a material can be defined at any given temperature, most commonly 25 degrees Celsius,
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Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring. They may be either simple aromatic rings or non-aromatic rings.
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Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone.
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organic compounds]] An organic compound is any member of a large class of chemical compounds whose molecules contain carbon; for historical reasons discussed below, a few types of compounds such as carbonates, carbon oxides and cyanides, as well as elemental carbon are
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Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring.[1] It is isomeric with two other forms of diazine.
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Imidazole is a heterocyclic aromatic organic compound. It is further classified as an alkaloid. Imidazole refers to the parent compound C3H4N2, whereas imidazoles are a class of heterocycles with similar ring structure but varying substituents.
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Tautomers are organic compounds that are interconvertible by a chemical reaction called tautomerization. As most commonly encountered, this reaction results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent
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Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring. They may be either simple aromatic rings or non-aromatic rings.
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A nucleic acid is a macromolecule composed of nucleotide chains. In biochemistry these molecules carry genetic information or form structures within cells. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
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For the programming language Adenine, see .


Adenine is a purine 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
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Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA; the others being adenine, cytosine, thymine, and uracil. With the formula C5H5N5
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hydrogen bond is a special type of dipole-dipole bond that exists between an electronegative atom and a hydrogen atom bonded to another electronegative atom. This type of bond always involves a hydrogen atom, thus the name.
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complementarity is a property of double-stranded nucleic acids such as DNA and RNA as well as DNA:RNA duplexes. Each strand is complementary to the other in that the base pairs between them are non-covalently connected via two or three hydrogen bonds.
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Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring.[1] It is isomeric with two other forms of diazine.
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5-methyluracil a pyrimidine nucleobase. As the name implies, thymine may be derived by methylation of uracil at the 5th carbon. In RNA thymine is replaced with uracil in most cases.
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Not to be confused with cysteine.


Cytosine is one of the five main nucleobases found in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and
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Left: An RNA strand, with its nitrogenous bases. Right: Double-stranded DNA.]] Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers, which plays several important roles in the processes of translating genetic information from
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Uracil is a pyrimidine which is common and naturally occurring.[1] Uracil was originally discovered in 1900. It was isolated by hydrolysis of yeast nuclein that was found in bovine thymus and spleen, herring sperm, and wheat germ.
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Hypoxanthine is a naturally occurring purine derivative.

It is occasionally found as a constituent of nucleic acids where it is present in the anticodon of tRNA in the form of its nucleoside inosine.
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Not to be confused with xanthene.


Xanthine (IPA: /ˈzænθiːn, ˈzænθaɪn]/
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Theobromine, also known as xantheose,[] is a bitter alkaloid of the cacao plant, and is therefore found in chocolate. It is in the methylxanthine class of chemical compounds,[1] which also includes the similar compounds theophylline and caffeine.
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