cytosine


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Related to cytosine: cytidine

cytosine

(sī`tōsēn'), organic base of the pyrimidinepyrimidine
, type of organic base found in certain coenzymes and in the nucleic acids of plant and animal tissue. The three major pyrimidines of almost universal distribution in living systems are cytosine, thymine, and uracil.
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 family. It was isolated from the nucleic acidnucleic 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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 of calf thymus tissue in 1894. A suggested structure for cytosine, published in 1903, was confirmed in the same year when that base was synthesized in the laboratory. Combined with the sugar ribose in glycosidic linkage, cytosine forms a derivative called cytidine (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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 CMP (cytidine monophosphate), CDP (cytidine diphosphate), and CTP (cytidine triphosphate). Analogous nucleosides and nucleotides are formed from cytosine and deoxyribose. The nucleoside derivatives of cytosine perform important functions in cellular metabolism. CTP 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 both carbohydrate and lipid metabolism; 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. CTP is the source of the cytidine found in ribonucleic acid (RNA) and deoxycytidine triphosphate (dCTP) is the source of the deoxycytidine in deoxyribonucleic acid (DNA). Thus cytosine is intimately involved in the preservation and transfer of genetic information.

Cytosine

 

(also 2-hydroxy-6-aminopyrimidine), a natural organic compound. A pyrimidine base, cytosine occurs as white crystals or thin, lustrous platelets. Its molecular weight is 111.1. It is found in all living cells as a component of nucleotides—that is, compounds that form nucleic acids, coenzymes, and certain other biologically active substances. The nucleoside cytidine consists of cytosine and the carbohydrate D-ribose.

cytosine

[′sīd·ə‚sēn]
(biochemistry)
C4H5ON3 A pyrimidine occurring as a fundamental unit or base of nucleic acids.
References in periodicals archive ?
Random mutagenesis and selection of Escherichia Coli Cytosine deaminase for cancer gene therapy.
SCE Polymeric film Guanine Adenine Thymine Cytosine Poly-2-aminophenol 0.
As with other methods relying on treatment of DNA with bisulfite, incomplete conversion of cytosine to uracil may be a problem and may cause false-positive results (19).
Carmel's group looked for places in the ancient DNA where cytosines had morphed into thymines.
By treating the neurons' DNA with a chemical that highlights methylated cytosines, and then sequencing the genomes, the researchers created a map showing how the pattern of methylation changes as the brain develops.
Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with epigenetic alterations, including genomic cytosine methylation.
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.
He was placed on a chemotherapeutic regimen of daunorubicin and cytosine arabinoside (ARA-C) for remission induction of AML.
Team member Yuichi Ando said among the four nitrogenous bases -- thymine (T), adenine (A), guanine and cytosine -- the researchers examined patient sequences of consecutive T and A bases called ''TATA boxes,'' which exist in genes activating enzymes that can prevent side effects of the drug.
BBD's mutation was shown to be a thymine mutated from a cytosine at the 2278 nucleotide location in the cDNA sequence causing a change from arginine to a stop codon at position 760 in the amino acid sequence.
The temperature at which the DNA fragment denatures, or separates into its individual strands, depends upon the length, sequence, and guanine cytosine (GC) nucleotide content of the fragment.
He required Cytosine in his spine and Vincristine - invariably fatal if administered incorrectly - in a vein to keep his condition at bay.