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(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.



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.


C5H5ON5 A purine base; occurs naturally as a fundamental component of nucleic acids.
References in periodicals archive ?
Protozoa are unable to synthesize purines or pyrimidines, but can incorporate free adenine, guanine and uracil into their nucleic acids.
Analysis of the Gly389Arg polymorphism was performed by BcgI, which was obtained from Bacillus coagulans where the substitution of cytosine with guanine formed a cutting region on DNA.
Three of the four bases found in DNA (adenine, guanine, and cytosine) also occur in RNA.
Nevertheless, they do not have GTPase activity and on the contrary, they exhibit activities such ribonuclease, methyltransferase, guanine deaminase, lactate dehydrogenase and others.
Zaikov co-wrote the papers reviewing fields of ozone applications, exploring the role of hydrogen binding in transition metal complex catalysts, and calculating the geometrical and electronic structure of adenine, cytosine, guanine, tymin and uracyl.
The DNA that makes up our genes comprises four " bases" or nucleotides-- cytosine, guanine, adenine and thymine.
At r=1/50, decrease of intensity was observed for the guanine band at 1710(20%), thymine at 1649(37%), adenine at 1610(35%), cytosine at 1492(14%), [PO.
We have recently demonstrated in collaboration with Anthony Pegg (Penn State University) for the first time that human alkyl guanine transferase can repair interstrand cross-linked DNA duplexes containing an alkyl linker of 7 methylene groups, whereas the protein is not able to repair a 4 carbon cross-link, and this work was recently published in the journal Biochemistry.
2-aminophenol, 3-aminophenol, 4-aminophenol, guanine 99 + %, adenine 99.
The RNA molecule is usually a single strand that folds into different shapes and consists of base units (adenine, guanine, cytosine, and uracil) bonded together with the sugar ribose.
Comparisons of the sequences of the four bases--adenine, cytosine, guanine and thymine--are used to identify genetic differences among living creatures from bacteria to humans.
The bird poo is said to be packed with the enzyme guanine, which is claimed to repair "tortured", dull skin.

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