Thymine

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Thymine
Thymine skeletal.svg
Thymine-3D-balls.png Thymine-3D-vdW.png
Identifiers
CAS number 65-71-4 YesY
PubChem 1135
ChemSpider 1103 N
UNII QR26YLT7LT YesY
MeSH Thymine
ChEBI CHEBI:17821 N
ChEMBL CHEMBL993 N
Jmol-3D images Image 1
Properties
Molecular formula C5H6N2O2
Molar mass 126.11 g mol−1
Density 1.23 g cm−3 (calculated)
Melting point 316 to 317 °C (601 to 603 °F; 589 to 590 K)
Boiling point 335 °C (635 °F; 608 K) (decomposes)
Acidity (pKa) 9.7
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Thymine /ˈθmɨn/ (T, Thy) is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase.

Derivation[edit]

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, thus 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]

Thymine is a nuclear base.

See also[edit]

References[edit]

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

External links[edit]