AskDefine | Define thymine

Dictionary Definition

thymine n : a base found in DNA (but not in RNA) and derived from pyrimidine; pairs with adenine [syn: T]

User Contributed Dictionary

English

Etymology

From thymic + -ine.

Pronunciation

  • /ˈθaɪmɪn/

Noun

  1. In the context of "biochemistry|genetics": A base, C5H6N2O2, obtained by applying sulphuric acid to thymic acid; it pairs with adenine in DNA.

Extensive Definition

For the similarly-spelled vitamin compound, see Thiamine
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.
thymine in Arabic: ثايمين
thymine in Bulgarian: Тимин
thymine in Catalan: Timina
thymine in Czech: Thymin
thymine in Danish: Thymin
thymine in German: Thymin
thymine in Modern Greek (1453-): Θυμίνη
thymine in Spanish: Timina
thymine in Esperanto: Timino
thymine in French: Thymine
thymine in Galician: Timina
thymine in Indonesian: Timin
thymine in Italian: Timina
thymine in Hebrew: תימין
thymine in Lithuanian: Timinas
thymine in Hungarian: Timin
thymine in Dutch: Thymine
thymine in Japanese: チミン
thymine in Norwegian: Tymin
thymine in Occitan (post 1500): Timina
thymine in Polish: Tymina
thymine in Portuguese: Timina
thymine in Russian: Тимин
thymine in Simple English: Thymine
thymine in Slovak: Tymín
thymine in Slovenian: Timin
thymine in Serbian: Тимин
thymine in Serbo-Croatian: Timin
thymine in Finnish: Tymiini
thymine in Swedish: Tymin
thymine in Thai: ไทมีน
thymine in Vietnamese: Thymine
thymine in Turkish: Timin
thymine in Ukrainian: Тимін
thymine in Chinese: 胸腺嘧啶
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