Thymine skeletal.svg
IUPAC name
Other names
3D model (JSmol)
ECHA InfoCard100.000.560
Molar mass126.115 g·mol−1
Density1.223 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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Thymine n/ (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. In RNA, thymine is replaced by the nucleobase uracil. Thymine was first isolated in 1893 by Albrecht Kossel and Albert Neumann from calves' thymus glands, hence its name.[1]


As its alternate name (5-methyluracil) 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, thereby 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 up to three phosphoric acid groups, producing dTMP (deoxythymidine monophosphate), dTDP, or dTTP (for the di- and tri- phosphates, respectively).

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.[2]

Other Languages
العربية: ثايمين
azərbaycanca: Timin
تۆرکجه: تیومین
Bân-lâm-gú: Thymin
беларуская: Тымін
български: Тимин
bosanski: Timin
brezhoneg: Timin
català: Timina
čeština: Thymin
dansk: Thymin
Deutsch: Thymin
eesti: Tümiin
Ελληνικά: Θυμίνη
español: Timina
Esperanto: Timino
euskara: Timina
فارسی: تیمین
français: Thymine
galego: Timina
한국어: 티민
հայերեն: Թիմին
हिन्दी: थायमिन
hrvatski: Timin
Bahasa Indonesia: Timina
italiano: Timina
עברית: תימין
Jawa: Timin
ქართული: თიმინი
қазақша: Тимин
kurdî: Tîmîn
lietuvių: Timinas
magyar: Timin
македонски: Тимин
Bahasa Melayu: Timina
Nederlands: Thymine
日本語: チミン
norsk: Tymin
occitan: Timina
polski: Tymina
português: Timina
română: Timină
русиньскый: Тимин
русский: Тимин
Scots: Thymine
Simple English: Thymine
slovenčina: Tymín
slovenščina: Timin
српски / srpski: Тимин
srpskohrvatski / српскохрватски: Timin
suomi: Tymiini
svenska: Tymin
Tagalog: Thymine
தமிழ்: தைமின்
ไทย: ไทมีน
Türkçe: Timin
українська: Тимін
Tiếng Việt: Thymine
吴语: 胸腺嘧啶
粵語: 胸腺嘧啶
中文: 胸腺嘧啶