guanine


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guanine

(gwä`nēn), organic base of the purinepurine,
type of organic base found in the nucleotides and nucleic acids of plant and animal tissue. The German chemist Emil Fischer did much of the basic work on purines and introduced the term into the chemical literature in the early 20th cent.
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 family. It was reported (1846) to be in the guanoguano
, dried excrement of sea birds and bats found principally on the coastal islands of Peru, Africa, Chile, and the West Indies. It contains about 6% phosphorus, 9% nitrogen, 2% potassium, and moisture. Guano is found mixed with feathers and bones and is used as a fertilizer.
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 of birds; later (1879–84) it was established as one of the major constituents of nucleic acidsnucleic acid,
any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis.
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. The accepted structure of the guanine molecule was proposed in 1875, and the compound was first synthesized in 1900. When combined with the sugar ribose in a glycosidic linkage, guanine forms a derivative called guanosine (a nucleoside), which in turn can be phosphorylated with from one to three phosphoric acid groups, yielding the three nucleotidesnucleotide
, organic substance that serves as a monomer in forming nucleic acids. Nucleotides consist of either a purine or a pyrimidine base, a ribose or deoxyribose, and a phosphate group. Adenosine triphosphate serves as the principle energy carrier for the cell's reactions.
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 GMP (guanosine monophosphate), GDP (guanosine diphosphate), and GTP (guanosine triphosphate). Analogous nucleosides and nucleotides are formed from guanine and deoxyribose. The nucleotide derivatives of guanine perform important functions in cellular metabolism. GTP acts as a coenzymecoenzyme
, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
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 in carbohydrate metabolism and in the biosynthesis of proteins; it can readily donate one of its phosphate groups to adenosine diphosphate (ADP) to form adenosine triphosphateadenosine triphosphate
(ATP) , organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves as the major energy source within the cell to drive a number of biological processes such as photosynthesis, muscle contraction, and the synthesis of
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 (ATP), an extremely important intermediate in the transfer of chemical energy in living systems. GTP is the source of the guanosine found in RNA and deoxyguanosine triphosphate (dGTP) is the source of the deoxyguanosine in DNA, and thus guanine is intimately involved in the preservation and transfer of genetic information. Guanine is said to account for the iridescence of fish scales and the white, shiny appearance of the skin of many amphibians and reptiles.

Guanine

 

2-amino-6-oxypurine. a purine base, widely distributed in animal and plant cells (it is a constituent of nucleic acids and is present in a free state).

It is the main component of the excrements of spiders and birds and was discovered in guano (hence the name). A considerable amount of guanine is present in the scales and skin of fish, reptiles, and amphibians. The calcium compound of guanine gives fish scales their characteristic shine. In mammal organisms, guanine is transformed into xanthine under the action of the enzyme guanase.

guanine

[′gwän‚ēn]
(biochemistry)
C5H5ON5 A purine base; occurs naturally as a fundamental component of nucleic acids.
References in periodicals archive ?
Sugiyama, "Possible cause of G-C [right arrow] C-G transversion mutation by guanine oxidation product, imidazolone," Chemistry & Biology, vol.
Nagamine, "Role of the amino terminal RHAU-specific motif in the recognition and resolution of guanine quadruplex-RNA by the DEAH-box RNAhelicase RHAU," Nucleic Acids Research, vol.
For 3'-GMP gel, the helical structure is formed by successive stacking of planar hydrogen-bonded guanine tetramers now known as the G-quartets on top of each other.
Kitade, "Cover Picture: Reduction-Responsive Guanine Incorporated into G-Quadruplex-Forming DNA (ChemBioChem 14/2016)," ChemBioChem, vol.
The most frequently observed nucleotide substitutions were a novel variant showing a nucleotide transversion from cytosine (C) to adenine (A) at the position 16173, a nucleotide transition from adenine (A) to guanine (G) at the position of 16175, and a nucleotide substitution from cytosine (C) to guanine (G) at the position of 16176 with the frequencies or 53%, 60%, and 82%, respectively.
Table 1 Lattice parameters for Flabellina iodinea crystals and known polymorphs of guanine Purified from Purified from Source F.
In place of guanine, RNA could have relied on a surrogate -- inosine.
Paradoxically, the guanine squares don't reflect light on their own - they're transparent.
Due to increased stability of its enol form, it is possible that 5-bromo uracil may pair with guanine instead of with adenine.
Hypoxanthine guanine phosphoribosyltransferase (HPRT) mutations in the Asian population.
VAL-083 (dianhydrogalactitol) is a first-in-class, DNA-targeting agent that introduces interstrand DNA cross-links at the N7-position of guanine leading to DNA double-strand breaks and cancer cell death.

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