Difference between revisions of "Guanine" - New World Encyclopedia

From New World Encyclopedia
m ({{Contracted}})
Line 7: Line 7:
 
! {{chembox header}} | General
 
! {{chembox header}} | General
 
|-  
 
|-  
−
| [[IUPAC nomenclature|Systematic name]]
+
| [[IUPAC nomenclature|Systematic name]]*
 
| 2-amino-1''H''-purin-6(9''H'')-one
 
| 2-amino-1''H''-purin-6(9''H'')-one
 
|-
 
|-
Line 13: Line 13:
 
| 2-amino-6-oxo-purine,<br />2-aminohypoxanthine,<br />Guanine
 
| 2-amino-6-oxo-purine,<br />2-aminohypoxanthine,<br />Guanine
 
|-
 
|-
−
| [[Chemical formula|Molecular formula]]
+
| [[Chemical formula|Molecular formula]]*
 
| C<sub>5</sub>H<sub>5</sub>N<sub>5</sub>O
 
| C<sub>5</sub>H<sub>5</sub>N<sub>5</sub>O
 
|-
 
|-
−
| [[Simplified molecular input line entry specification|SMILES]] <!-- mostly for organic compounds, omit otherwise —>
+
| [[Simplified molecular input line entry specification|SMILES]]* <!-- mostly for organic compounds, omit otherwise —>
 
| NC(NC1=O)=NC2=C1N=CN2
 
| NC(NC1=O)=NC2=C1N=CN2
 
|-
 
|-
−
| [[Molar mass]]
+
| [[Molar mass]]*
 
| 151.1261 g/mol
 
| 151.1261 g/mol
 
|-
 
|-
Line 25: Line 25:
 
| White amorphous solid.
 
| White amorphous solid.
 
|-
 
|-
−
| [[CAS registry number|CAS number]]
+
| [[CAS registry number|CAS number]]*
 
| {{CASREF|CAS=73-40-5}}
 
| {{CASREF|CAS=73-40-5}}
 
|-
 
|-
 
! {{chembox header}} | Properties
 
! {{chembox header}} | Properties
 
|-
 
|-
−
| [[Density]] and [[Phase (matter)|phase]]
+
| [[Density]]* and [[Phase (matter)|phase]]
 
| ? g/cm<sup>3</sup>, solid.
 
| ? g/cm<sup>3</sup>, solid.
 
|-
 
|-
−
| [[Solubility]] in [[Water (molecule)|water]]
+
| [[Solubility]] in [[Water (molecule)|water]]*
 
| Insoluable.
 
| Insoluable.
 
|-
 
|-
Line 39: Line 39:
 
<!-- | solubility info on other solvents —>
 
<!-- | solubility info on other solvents —>
 
<!-- |- —>
 
<!-- |- —>
−
| [[Melting point]]
+
| [[Melting point]]*
 
| 360°C (633.15 K) ''deco.''
 
| 360°C (633.15 K) ''deco.''
 
|-
 
|-
−
| [[Boiling point]]
+
| [[Boiling point]]*
 
| Sublimes.
 
| Sublimes.
 
|-
 
|-
 
! {{chembox header}} | Structure
 
! {{chembox header}} | Structure
 
|-
 
|-
−
| [[Crystal structure]] <!-- omit if not a solid —>
+
| [[Crystal structure]]* <!-- omit if not a solid —>
 
| ? <!-- e.g. [[triclinic]], [[monoclinic]], [[orthorhombic]], [[hexagonal]], [[rhombohedral|trigonal]], [[tetragonal]], [[cubic]], and mention "close packed" or similar.  You may also cite what class it belongs to, e.g. [[Cadmium chloride#Crystal structure|CdCl<sub>2</sub>]]  —>
 
| ? <!-- e.g. [[triclinic]], [[monoclinic]], [[orthorhombic]], [[hexagonal]], [[rhombohedral|trigonal]], [[tetragonal]], [[cubic]], and mention "close packed" or similar.  You may also cite what class it belongs to, e.g. [[Cadmium chloride#Crystal structure|CdCl<sub>2</sub>]]  —>
 
|-
 
|-
−
| [[Dipole#Molecular dipoles|Dipole moment]]
+
| [[Dipole#Molecular dipoles|Dipole moment]]*
 
| ? [[Debye|D]]
 
| ? [[Debye|D]]
 
|-
 
|-
 
! {{chembox header}} | Hazards <!--  Summary only- MSDS entry provides more complete information —>
 
! {{chembox header}} | Hazards <!--  Summary only- MSDS entry provides more complete information —>
 
|-
 
|-
−
| [[Material safety data sheet|MSDS]]
+
| [[Material safety data sheet|MSDS]]*
−
| [[Guanine (data page)#Material Safety Data Sheet|External MSDS]] <!-- please replace with proper link—>
+
| [[Guanine (data page)#Material Safety Data Sheet|External MSDS]]* <!-- please replace with proper link—>
 
|-
 
|-
−
| Main [[Worker safety and health|hazard]]s
+
| Main [[Worker safety and health|hazard]]*s
 
| Irritant.
 
| Irritant.
 
|-
 
|-
−
| [[NFPA 704]]
+
| [[NFPA 704]]*
 
| {{NFPA 704 | Health=1 | Flammability=1 }}
 
| {{NFPA 704 | Health=1 | Flammability=1 }}
 
|-
 
|-
−
| [[Flash point]]
+
| [[Flash point]]*
 
| Non-flammable.
 
| Non-flammable.
 
|-
 
|-
−
| [[Risk and Safety Statements|R/S statement]]
+
| [[Risk and Safety Statements|R/S statement]]*
−
| [[List of R-phrases|R]]: {{R36}}, {{R37}}, {{R38}}. <br /> [[List of S-phrases|S]]: {{R24/25}}, {{R26}}, {{R36}}.
+
| [[List of R-phrases|R]]*: {{R36}}, {{R37}}, {{R38}}. <br /> [[List of S-phrases|S]]*: {{R24/25}}, {{R26}}, {{R36}}.
 
|-
 
|-
−
| [[RTECS]] number
+
| [[RTECS]]* number
 
| MF8260000
 
| MF8260000
 
|-
 
|-
−
! {{chembox header}} | [[Guanine (data page)|Supplementary data page]]
+
! {{chembox header}} | [[Guanine (data page)|Supplementary data page]]*
 
|-
 
|-
−
| [[Guanine (data page)#Structure and properties|Structure and<br />properties]]  
+
| [[Guanine (data page)#Structure and properties|Structure and<br />properties]]*
−
| [[Refractive index|''n'']], [[Dielectric constant|ε<sub>r</sub>]], etc.  
+
| [[Refractive index|''n'']]*, [[Dielectric constant|ε<sub>r</sub>]]*, etc.  
 
|-
 
|-
−
| [[Guanine (data page)#Thermodynamic properties|Thermodynamic<br />data]]  
+
| [[Guanine (data page)#Thermodynamic properties|Thermodynamic<br />data]]*
 
| Phase behaviour<br />Solid, liquid, gas  
 
| Phase behaviour<br />Solid, liquid, gas  
 
|-
 
|-
−
| [[Guanine (data page)#Spectral data|Spectral data]]
+
| [[Guanine (data page)#Spectral data|Spectral data]]*
−
| [[UV/VIS spectroscopy|UV]], [[Infrared spectroscopy|IR]], [[nuclear magnetic resonance spectroscopy|NMR]], [[Mass spectrometry|MS]]
+
| [[UV/VIS spectroscopy|UV]]*, [[Infrared spectroscopy|IR]]*, [[nuclear magnetic resonance spectroscopy|NMR]]*, [[Mass spectrometry|MS]]
 
|-
 
|-
 
! {{chembox header}} | Related compounds
 
! {{chembox header}} | Related compounds
Line 95: Line 95:
 
| [[cytosine|Cytosine]],<br />[[adenine|Adenine]],<br />[[thymine|Thymine]],<br />[[uracil|Uracil]]
 
| [[cytosine|Cytosine]],<br />[[adenine|Adenine]],<br />[[thymine|Thymine]],<br />[[uracil|Uracil]]
 
|-
 
|-
−
| {{chembox header}} | <small>Except where noted otherwise, data are given for<br /> materials in their [[standard state|standard state (at 25°C, 100 kPa)]]<br />[[wikipedia:Chemical infobox|Infobox disclaimer and references]]</small>
+
| {{chembox header}} | <small>Except where noted otherwise, data are given for<br /> materials in their [[standard state|standard state (at 25°C, 100 kPa)]]*<br /></small>
 
|-
 
|-
 
|}
 
|}
−
'''Guanine''' is one of the five main [[nucleobase]]s found in the [[nucleic acid]]s [[DNA]] and [[RNA]]; the others being [[adenine]], [[cytosine]], [[thymine]], and [[uracil]].  With the formula C<sub>5</sub>H<sub>5</sub>N<sub>5</sub>O, 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]].
+
'''Guanine''' is one of the five main [[nucleobase]]s found in the [[nucleic acid]]s [[DNA]] and [[RNA]]; the others being [[adenine]], [[cytosine]], [[thymine]], and [[uracil]].  With the formula C<sub>5</sub>H<sub>5</sub>N<sub>5</sub>O, guanine is a [[purine]] derivative, 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.
 +
 
 +
In DNA, adenine and guanine, which are purine derivatives, form hydrogen bonds with their complementary pyrimidine derivatives, thymine and cytosine. In RNA, the complement of adenine is uracil instead of thymine.
  
 
==Basic principles==
 
==Basic principles==

Revision as of 14:53, 30 December 2006

Guanine
Guanine
General
Systematic name 2-amino-1H-purin-6(9H)-one
Other names 2-amino-6-oxo-purine,
2-aminohypoxanthine,
Guanine
Molecular formula C5H5N5O
SMILES NC(NC1=O)=NC2=C1N=CN2
Molar mass 151.1261 g/mol
Appearance White amorphous solid.
CAS number [73-40-5] [1]
Properties
Density and phase ? g/cm3, solid.
Solubility in water Insoluable.
Melting point 360°C (633.15 K) deco.
Boiling point Sublimes.
Structure
Crystal structure ?
Dipole moment ? D
Hazards
MSDS External MSDS
Main hazards Irritant.
NFPA 704

NFPA 704.svg

1
1
0
 
Flash point Non-flammable.
R/S statement R: R36, R37, R38.
S: R24/25, R26, R36.
RTECS number MF8260000
Supplementary data page
Structure and
properties 		n, εr, etc.
Thermodynamic
data 		Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Other anions ?
Other cations ?
Related compounds Cytosine,
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 purine derivative, 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.

In DNA, adenine and guanine, which are purine derivatives, form hydrogen bonds with their complementary pyrimidine derivatives, thymine and cytosine. In RNA, the complement of adenine is uracil instead of thymine.

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.

Cytonum2.png Guannum2.png

Isolation, background, & some chemistry

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

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.

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. Guaninesynth.png

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.

References
ISBN links support NWE through referral fees

1. 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. <br\> 2. 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. <br\> 3. Lister, J.H. "Part II Purines." The Chemistry of Heterocyclic Compounds. Wiley-Interscience (New York). 1971.

External links


Nucleic acids edit
Nucleobases: Adenine - Thymine - Uracil - Guanine - Cytosine - Purine - Pyrimidine
Nucleosides: Adenosine - Uridine - Guanosine - Cytidine - Deoxyadenosine - Thymidine - Deoxyguanosine - Deoxycytidine
Nucleotides: AMP - UMP - GMP - CMP - ADP - UDP - GDP - CDP - ATP - UTP - GTP - CTP - cAMP - cGMP
Deoxynucleotides: dAMP - dTMP - dUMP - dGMP - dCMP - dADP - dTDP - dUDP - dGDP - dCDP - dATP - dTTP - dUTP - dGTP - dCTP
Nucleic acids: DNA - RNA - LNA - PNA - mRNA - ncRNA - miRNA - rRNA - siRNA - tRNA - mtDNA - Oligonucleotide

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.

Retrieved from https://www.newworldencyclopedia.org/p/index.php?title=Guanine&oldid=170183

Content is available under Creative Commons Attribution/Share-Alike License; additional terms may apply. See Terms of Use for details.
Copyright Logo
Powered by MediaWiki