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Information about Guanine









Guanine
IUPAC name2-amino-1H-purin-6(9H)-one
Other names2-amino-6-oxo-purine,
2-aminohypoxanthine,
Guanine
Identifiers
CAS number73-40-5
RTECS numberMF8260000
SMILESNC1=Nc2[nH]cnc2C(=O)N1
Properties
Molecular formulaC5H5N5O
Molar mass151.1261 g/mol
AppearanceWhite amorphous solid.
Density, solid.
Melting point 360°C (633.15 K) deco.
Boiling point Sublimes.
Solubility in waterInsoluble.
Dipole moment? D
Hazards
Main hazardsIrritant.
NFPA 704
1
1
0
 
Flash pointNon-flammable.
Related Compounds
Related compoundsCytosine; Adenine; Thymine; Uracil
Except where noted otherwise, data are given for
materials in their standard state
(at 25 C, 100 kPa)
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 C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine-imidazole ring system with conjugated double bonds. Being unsaturated, the bicyclic molecule is planar. The guanine nucleoside is called guanosine.

Basic principles

Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA and uracil only in RNA. Guanine has two tautomeric forms, the keto form and enol form. It binds to cytosine through three hydrogen bonds. In cytosine, the amino group acts as the hydrogen donor and the C-2 carbonyl and the N-3 amine as the hydrogen-bond acceptors. Guanine has a group at C-6 that acts as the hydrogen acceptor, while the group at N-1 and the amino group at C-2 acts as the hydrogen donors.

Isolation, background, & some chemistry

The first isolation of guanine was reported in 1844 from the excreta of sea birds,[1] known as guano, which was used as a source of fertilizer. About fifty years later, Fischer determined the structure and also showed that uric acid can be converted to guanine.[2] The first complete synthesis was done by Traube and remains among the best large-scale preparations.[3]

Guanine can be hydrolyzed with strong acid to glycine, ammonia, carbon dioxide, and carbon monoxide at 180°C. Guanine oxidizes more readily than adenine, the other purine-derivative base in DNA and RNA. Its high melting point of 350°C reflects the intermolecular hydrogen bonding between the oxo and amino groups in the molecules in the crystal. Because of this intermolecular bonding, guanine is relatively insoluble in water, although it is soluble in dilute acids and bases.

Syntheses

Trace amounts of guanine form by the polymerization of ammonium cyanide (NH4CN). Two experiments conducted by Levy et al., showed that heating 10 M NH4CN at 80°C for 24 hours gave a yield of 0.0007% while using 0.1 M NH4CN frozen at -20°C for 25 years gave a 0.0035% yield. These results indicate guanine could arise in frozen regions of the primitive earth. In 1984, Yuasa reported a 0.00017% yield of guanine after the electrical discharge of NH3, CH4, C2H6, and 50 mL of water, followed by a subsequent acid hydrolysis. However, it is unknown if the presence of guanine was not simply resulted from a contaminant of the reaction.[4]

5NH3 + CH4 + 2C2H6 + H2O → C5H8N5O (guanine) + (25/2)H2


A Fischer-Tropsch synthesis can also be used to form guanine, along with adenine, uracil and thymine. Heating an equimolar gas mixture of CO, H2, and NH3 to 700 °C for 0.24 to 0.4 hours, followed by quick cooling and then sustainted reheating to 100-200°C for 16-44 hours with an alumina catalyst yielded guanine and uracil:
5CO + (1/2)H2 + 5NH3 → C5H8N5O (guanine) + 4H2O


Traube's synthesis involves heating 2,4,5-triamino-1,6-dihydro-6-oxypyrimidine (as the sulphate) with formic acid for several hours.

Other uses

In 1656 in Paris, François Jaquin (a rosary maker) extracted from scales of some fishes the so called pearl essence, crystalline guanine forming G-quadruplexes: in cosmetic industry, crystalline guanine is used as an additive to various products (e.g., shampoos), where it provides the pearly iridescent effect. It is also used in metallic paints and simulated pearls and plastics. It provides shimmering lustre to eye shadow and nail polish. Guanine crystals are rhombic platelets composed of multiple, transparent layers but they have a high index of refraction that partially reflects and transmits light from layer to layer thus producing a pearly luster. It can be applied by spray, painting or dipping. It may irritate eyes. Its alternatives are mica, synthetic pearl, and aluminium and bronze particles.

See also

References

1. ^ Hitchings, George H.; Elvira A. Falco (1944-10-15). "The Identification of Guanine in Extracts of Girella Nigricans". Proc Natl Acad Sci 30 (10): 294-297. Retrieved on 2007-10-18. 
2. ^ Emil Fischer: The Nobel Prize in Chemistry, 1902] - nobelprize.org
3. ^ Wilhelm Traube, Chem. Ber., 33, 1900, 1371-79
4. ^ Levy, Matthew; Stanley L. Miller, John Oró (August 1999). "Production of Guanine from NH4CN Polymerizations". Journal of Molecular Evolution 49 (2): 165-168. DOI:10.1007/PL00006539. Retrieved on 2007-10-18.  - quotes the Yuasa paper and cites the possibility of there being a contaminant in the reaction.
  • Miyakawa, S., Murasawa, K., Kobayashi, K., Sawaoka, AB. "Abiotic synthesis of guanine with high-temperature plasma." Orig Life Evol Biosph. 30(6): 557-66, Dec. 2000.
  • Horton, H.R., Moran, L.A., Ochs, R.S., Rawn, J.D., Scrimgeour, K.G. "Principles of Biochemistry." Prentice Hall (New Jersey). 3rd Edition, 2002.
  • Lister, J.H. "Part II Purines." The Chemistry of Heterocyclic Compounds. Wiley-Interscience (New York). 1971.

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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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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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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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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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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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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Nucleobases are the parts of RNA and DNA that may be involved in pairing (see also base pairs). These include cytosine, guanine, adenine, thymine (DNA), uracil (RNA) and xanthine and hypoxanthine (mutated forms of guanine and adenine, respectively).
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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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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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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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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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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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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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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.
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Nucleosides are glycosylamines made by attaching a nucleobase (often referred to simply as bases) to a ribose or deoxyribose ring. Examples of these include cytidine, uridine, adenosine, guanosine, thymidine and inosine. In short, a nucleoside is a base linked to sugar.
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Guanosine is a nucleoside comprising guanine attached to a ribose (ribofuranose) ring via a β-N9-glycosidic bond.

Guanosine can be phosphorylated to become GMP (guanosine monophosphate), cGMP (cyclic guanosine monophosphate), GDP (guanosine diphosphate) and
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