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2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Guanine? Wrong! If the Guanine is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Guanine then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Guanine? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Guanine and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Guanine wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Guanine then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Guanine site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Guanine, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Guanine, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
{{Chembox new| Name = Guanine| ImageFile = Guanine chemical structure.png| ImageSize = 200px| ImageName = Guanine| IUPACName = 2-amino-1
H-purin-6(9
H)-one| OtherNames = 2-amino-6-oxo-purine,
2-aminohypoxanthine,
Guanine| Section1 = {{Chembox Identifiers| SMILES = NC1=Nc2cnc2C(=O)N1| CASNo = 73-40-5| RTECS = MF8260000 -->
| Section2 = {{Chembox Properties| Formula = C5H5N5O| MolarMass = 151.1261 g/mol| Appearance = White amorphous solid.| Density = , solid.| Solubility = Insoluble.| MeltingPt = 360°C (633.15 K)
deco.| BoilingPt = Sublimes.| Dipole = ?
Debye -->
| Section7 = {{Chembox Hazards| MainHazards = Irritant.| NFPA-H = 1| NFPA-F = 1| NFPA-R =| FlashPt = Non-flammable. -->| Section8 = {{Chembox Related
| OtherAnions =| OtherCations =| OtherCpds =
Cytosine;
Adenine; Thymine; Uracil -->
-->
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-enol tautomerism.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.{| align="center"|-|width="325px"| |width="325px"| |}
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 later, Fischer determined the structure and also showed that uric acid can be converted to guanine. Emil Fischer: The Nobel Prize in Chemistry, 1902] - nobelprize.org The first complete synthesis was done by Wilhelm Traube and remains among the best large-scale preparations.
Wilhelm Traube, Chem. Ber., 33, 1900, 1371-79
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. - quotes the Yuasa paper and cites the possibility of there being a contaminant in 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.
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
iridescence 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
- 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
- Computational Chemistry Wiki
- Good Guanine reference
{{Chembox new| Name = Guanine| ImageFile = Guanine chemical structure.png| ImageSize = 200px| ImageName = Guanine| IUPACName = 2-amino-1
H-purin-6(9
H)-one| OtherNames = 2-amino-6-oxo-purine,
2-aminohypoxanthine,
Guanine| Section1 = {{Chembox Identifiers| SMILES = NC1=Nc2cnc2C(=O)N1| CASNo = 73-40-5| RTECS = MF8260000 -->
| Section2 = {{Chembox Properties| Formula = C5H5N5O| MolarMass = 151.1261 g/mol| Appearance = White amorphous solid.| Density = , solid.| Solubility = Insoluble.| MeltingPt = 360°C (633.15 K)
deco.| BoilingPt = Sublimes.| Dipole = ? Debye -->
| Section7 = {{Chembox Hazards| MainHazards = Irritant.| NFPA-H = 1| NFPA-F = 1| NFPA-R =| FlashPt = Non-flammable. -->| Section8 = {{Chembox Related
| OtherAnions =| OtherCations =| OtherCpds =
Cytosine;
Adenine;
Thymine;
Uracil -->
-->
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-enol tautomerism.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.{| align="center"|-|width="325px"| |width="325px"| |}
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 later, Fischer determined the structure and also showed that uric acid can be converted to guanine. Emil Fischer: The Nobel Prize in Chemistry, 1902] - nobelprize.org The first complete synthesis was done by Wilhelm Traube and remains among the best large-scale preparations.Wilhelm Traube, Chem. Ber., 33, 1900, 1371-79
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. - quotes the Yuasa paper and cites the possibility of there being a contaminant in 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.
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 iridescence 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
- 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
- Computational Chemistry Wiki
- Good Guanine reference
Guanine - Wikipedia, the free encyclopedia
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 C 5 H 5 N 5 O, guanine ...
guanine
Guanine is one of the four bases which form pairs to make up the rungs of the DNA helix. Guanine (G) forms a pair with a base called Cytosine (C)
Definition: guanine from Online Medical Dictionary
The Online Medical Dictionary is a searchable dictionary of definitions from medicine, science and technology.
Definition: guanine deaminase from Online Medical Dictionary
The Online Medical Dictionary is a searchable dictionary of definitions from medicine, science and technology.
genome.gov | Talking Glossary: "guanine"
Easy-to-use, talking glossary of genetic terms, produced by the National Human Genome Research Institute.
guanine - definition of guanine in the Medical dictionary - by the ...
guanine /gua·nine/ (gwah´nen) a purine base, in animal and plant cells usually occurring condensed with ribose or deoxyribose to form guanosine and deoxyguanosine, constituents ...
SCOP: Protein: Archaeosine tRNA-guanine transglycosylase, N-terminal ...
Protein: Archaeosine tRNA-guanine transglycosylase, N-terminal domain from Archaeon Pyrococcus horikoshii Lineage: Root: scop; Class: Alpha and beta proteins (a/b) [51349]
SCOP: Protein: Archaeosine tRNA-guanine transglycosylase, C2 domain ...
Protein: Archaeosine tRNA-guanine transglycosylase, C2 domain from Archaeon Pyrococcus horikoshii Lineage: Root: scop; Class: Alpha and beta proteins (a+b) [53931]
guanine - Hutchinson encyclopedia article about guanine
Seventh letter of the English alphabet. It was formed by the Romans by adding a tail to the letter C, which represented the /k/ sound.
Curtis DNA Models: Thymine-Adenine, Cytosine-Guanine
Alternative DNS Base pairs deriving from New Scientist article ... For further details, see New Scientist, May 16, 1998. To view these models, install either (a) the Chime or (b ...
