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Thymine



For the similarly-spelled vitamin compound, see Thiamine
Thymine
IUPAC name 5-Methylpyrimidine-2,4(1H,3H)-dione
Identifiers
CAS number 65-71-4
MeSH Thymine
SMILES CC1=CNC(=O)NC1=O
Properties
Molecular formula C5H6N2O2
Molar mass 126.11334 g/mol
Melting point

316 - 317 °C

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Thymine is one of the four bases in the nucleic acid of DNA that make up the letters ATGC. The others are adenine, guanine, and cytosine. Thymine (T) always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be derived by methylation of uracil at the 5th carbon. In RNA, thymine is replaced with uracil in most cases. In DNA, thymine(T) binds to adenine (A) via two hydrogen bonds to assist in stabilizing the nucleic acid structures.

Thymine combined with deoxyribose creates the nucleoside deoxythymidine, which is synonymous with the term thymidine. Thymidine can be phosphorylated with one, two, or three phosphoric acid groups, creating, respectively, TMP, TDP, or TTP (thymidine mono-, di-, or triphosphate).

One of the common mutations of DNA involves two adjacent thymines or cytosine, which, in presence of ultraviolet light, may form thymine dimers, causing "kinks" in the DNA molecule that inhibit normal function.

Thymine could also be a target for actions of 5-fluorouracil (5-FU) in cancer treatment. 5-FU can be a metabolic analog of thymine (in DNA synthesis) or uracil (in RNA synthesis). Substitution of this analog inhibits DNA synthesis in actively-dividing cells.

Thymine bases are frequently oxidized to hydantoins over time after the death of an organism[1].

References

  1. ^ Hofreiter M., Serre D., Poinar H.N., Kuch M., and Paabo S. Nature Reviews Genetics (2001) 2:353.

See also


Nucleobases: Purine (Adenine, Guanine) | Pyrimidine (Uracil, Thymine, Cytosine)
Nucleosides: Adenosine/Deoxyadenosine | Guanosine/Deoxyguanosine | Uridine | Thymidine | Cytidine/Deoxycytidine
Nucleotides: monophosphates (AMP, GMP, UMP, CMP) | diphosphates (ADP, GDP, UDP, CDP) | triphosphates (ATP, GTP, UTP, CTP) | cyclic (cAMP, cGMP, cADPR)
Deoxynucleotides: monophosphates (dAMP, dGMP, TMP, dCMP) | diphosphates (dADP, dGDP, TDP, dCDP) | triphosphates (dATP, dGTP, TTP, dCTP)
Ribonucleic acids: RNA | mRNA (pre-mRNA/hnRNA) | tRNA | rRNA | gRNA | miRNA | ncRNA | piRNA | shRNA | siRNA | snRNA | snoRNA
Deoxyribonucleic acids: DNA | cDNA | gDNA | msDNA | mtDNA
Nucleic acid analogues: GNA | LNA | PNA | TNA | morpholino
Cloning vectors: phagemid | plasmid | lambda phage | cosmid | P1 phage | fosmid | BAC | YAC | HAC
  This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Thymine". A list of authors is available in Wikipedia.
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