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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/01 04:28:42」(JST)

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Thymine /ˈθaɪmɨn/ (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 (from calves' thymus glands) in 1893 by Albrecht Kossel and Albert Neumann.^[1]

Derivation

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.^[2]

Thymine is a nuclear base.

Theoretical aspects

In March 2015, NASA scientists reported that, for the first time, complex DNA and RNA organic compounds of life, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as pyrimidine, found in meteorites. Pyrimidine, like polycyclic aromatic hydrocarbons (PAHs), the most carbon-rich chemical found in the Universe, may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists.^[3]

References

^ Albrecht Kossel and Albert Neumann (1893) "Ueber das Thymin, ein Spaltungsproduct der Nucleïnsäure" (On thymine, a cleavage product of nucleic acid), Berichte der Deutschen Chemischen Gesellschaft zu Berlin, 26 : 2753-2756. From p. 2754: "Wir bezeichnen diese Substanz als Thymin." (We designate this substance as "thymine" [because it was initially obtained from the thymus glands of calves].)
^ Hofreiter M., Serre D., Poinar H.N., Kuch M., and Paabo S. Nature Reviews Genetics (2001) 2:353.
^ Marlaire, Ruth (3 March 2015). "NASA Ames Reproduces the Building Blocks of Life in Laboratory". NASA. Retrieved 5 March 2015.

External links

Thymine MS Spectrum
Infoplease Encyclopedia
Science Aid: DNA Structure and Replication

English Journal

A distance-dependent metal-enhanced fluorescence sensing platform based on molecular beacon design.

Zhou Z, Huang H, Chen Y, Liu F, Huang CZ, Li N.Author information Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.AbstractA new metal-enhanced fluorescence (MEF) based platform was developed on the basis of distance-dependent fluorescence quenching-enhancement effect, which combined the easiness of Ag-thiol chemistry with the MEF property of noble-metal structures as well as the molecular beacon design. For the given sized AgNPs, the fluorescence enhancement factor was found to increase with a d(6) dependency in agreement with fluorescence resonance energy transfer mechanism at shorter distance and decrease with a d(-3) dependency in agreement with plasmonic enhancement mechanism at longer distance between the fluorophore and the AgNP surface. As a proof of concept, the platform was demonstrated by a sensitive detection of mercuric ions, using thymine-containing molecular beacon to tune silver nanoparticle (AgNP)-enhanced fluorescence. Mercuric ions were detected via formation of a thymine-mercuric-thymine structure to open the hairpin, facilitating fluorescence recovery and AgNP enhancement to yield a limit of detection of 1 nM, which is well below the U.S. Environmental Protection Agency regulation of the Maximum Contaminant Level Goal (10nM) in drinking water. Since the AgNP functioned as not only a quencher to reduce the reagent blank signal but also an enhancement substrate to increase fluorescence of the open hairpin when target mercuric ions were present, the quenching-enhancement strategy can greatly improve the detection sensitivity and can in principle be a universal approach for various targets when combined with molecular beacon design.
Biosensors & bioelectronics.Biosens Bioelectron.2014 Feb 15;52:367-73. doi: 10.1016/j.bios.2013.09.013. Epub 2013 Sep 19.
A new metal-enhanced fluorescence (MEF) based platform was developed on the basis of distance-dependent fluorescence quenching-enhancement effect, which combined the easiness of Ag-thiol chemistry with the MEF property of noble-metal structures as well as the molecular beacon design. For the given s
PMID 24080216

Homozygosity mapping identifies a GALK1 mutation as the cause of autosomal recessive congenital cataracts in 4 adult siblings.

Chacon-Camacho OF1, Buentello-Volante B1, Velázquez-Montoya R2, Ayala-Ramirez R1, Zenteno JC3.Author information 1Research Unit-Genetics, Institute of Ophthalmology, "Conde de Valenciana", Mexico City, Mexico.2Cornea Department, "Dra. Olga Montoya" Ophthalmic Center, San Jose, Costa Rica.3Research Unit-Genetics, Institute of Ophthalmology, "Conde de Valenciana", Mexico City, Mexico; Department of Biochemistry, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico. Electronic address: jczenteno@institutodeoftalmologia.org.AbstractOBJECTIVE: Monogenic congenital cataract is one of the most genetically heterogeneous ocular conditions with almost 30 different genes involved in its etiology. In adult patients, genotype-phenotype correlations are troubled by eye surgery during infancy and/or long-term ocular complications. Here, we describe the molecular diagnosis of GALK1 deficiency as the cause of autosomal recessive congenital cataract in a family from Costa Rica.
Gene.Gene.2014 Jan 25;534(2):218-21. doi: 10.1016/j.gene.2013.10.057. Epub 2013 Nov 7.
OBJECTIVE: Monogenic congenital cataract is one of the most genetically heterogeneous ocular conditions with almost 30 different genes involved in its etiology. In adult patients, genotype-phenotype correlations are troubled by eye surgery during infancy and/or long-term ocular complications. Here,
PMID 24211322

Japanese Journal

Synthesis of 5-Methyluridine by a Thermophile, Bacillus stearothermophilus JTS 859

HORI Nobuaki,WATANABE Mutsumi,YAMAZAKI Yoshinari,MIKAMI Yoichi
Agricultural and Biological Chemistry 53(1), 197-202, 1989
… Many thermophiles, which can grow at 65°C, were examined as to their ability to produce 5-methyluridine from inosine and thymine (5-methyluracil) in the presence of phosphate and cells as enzyme sources. … Bacillus stearothermophilus JTS 859 was selected as a strain that synthesized 5-methyluridine efficiently. …
NAID 130000024228

A Facile Synthetic Method for Pyrimidine Acyclonucleoside Derivatives

越智清成,宮本勝仁,三浦裕,光井碩樹,松永功,新藤実
Chemical & pharmaceutical bulletin 33(4), 1703-1706, 1985-04-25
… Treatment of these reaction mixtures with methanol containing sodium hydrogen carbonate or aqueous sodium hydroxide gives pyrimidine acyclonucleosides (5a-g). …
NAID 110003625577

Synthetic Studies of Potential Antimetabolites. XI. Syntheses of β-D-Pentofuranosyl-5-methylcytosines

水野義久,上田享,池田一芳,三浦一伸
Chemical & pharmaceutical bulletin 16(2), 262-268, 1968-02-25
… 1-(β-D-Arabinofuranosyl)-5-methylcytosine (III) was prepared by amination and subsequent deblocking of 1-(2', 3', 5'-tri-O-benzyl-β-D-arabinofuranosyl)-4-methoxy-5-methyl-1H-pyrimidine-2-one which had been prepared from 2,4-dimethoxy-5-methylpyrimidine and 1-(2', 3', 5'-tri-O-benzyl-α-D-arabinofuranosyl) chloride. …
NAID 110003661497

Related Pictures

別名 (英名) 5-Methyluracil thymine: Definition from Answers.com Methyluracil tablets 500mg #10 Thymine (5 Methyluracil; 5-Methyluracil) methylpyrimidine 5 methyluracil cas no Methyluracil = Thymin (!)

★リンクテーブル★

リンク元	「チミン」「5-メチルウラシル」

「チミン」

Thymine
Names
	IUPAC name 5-Methylpyrimidine-2,4(1H,3H)-dione
	Other names 5-methyluracil
Identifiers
CAS Registry Number	65-71-4
ChEBI	CHEBI:17821
ChEMBL	ChEMBL993
ChemSpider	1103
	InChI InChI=1S/C5H6N2O2/c1-3-2-6-5(9)7-4(3)8/h2H,1H3,(H2,6,7,8,9) ; Key: RWQNBRDOKXIBIV-UHFFFAOYSA-N ; InChI=1/C5H6N2O2/c1-3-2-6-5(9)7-4(3)8/h2H,1H3,(H2,6,7,8,9); Key: RWQNBRDOKXIBIV-UHFFFAOYAL ;
IUPHAR/BPS	4581
Jmol-3D images	Image
MeSH	Thymine
PubChem	1135
	SMILES Cc1c[nH]c(=O)[nH]c1=O ;
UNII	QR26YLT7LT
Properties
Chemical formula	C5H6N2O2
Molar mass	126.12 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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	verify (what is: /?)
	Infobox references

　　[★]

英: thymine Thy
同: 5-メチルウラシル 5-methyluracil
関: ピリミジン、塩基、核酸

塩基の一種
ピリミジン塩基

派生化合物 FB.29

		プリン塩基		ピリミジン塩基
塩基		アデニン	グアニン	シトシン	チミン	ウラシル
		Ade	Gua	Cyt	Thy	Ura
		A	G	C	T	U
ヌクレオシド		アデノシン	グアノシン	シチジン	デオキシチミジン	ウリジン
		Ado	Guo	Cyd	dThd	Urd
		A	G	C	dT	U
ヌクレオチド		アデニル酸	グアニル酸	シチジル酸	デオキシチミジル酸	ウリジル酸
		アデノシン一リン酸	グアノシン一リン酸	シチジン一リン酸	デオキシチミジン一リン酸	ウリジン一リン酸
	for DNA	dAMP	dGMP	dCMP	dTMP
	for RNA	AMP	GMP	CMP		UMP

「5-メチルウラシル」

　　[★]

英: 5-methyluracil
関: チミン

[1] Albrecht Kossel and Albert Neumann (1893) "Ueber das Thymin, ein Spaltungsproduct der Nucleïnsäure" (On thymine, a cleavage product of nucleic acid), Berichte der Deutschen Chemischen Gesellschaft zu Berlin, 26 : 2753-2756. From p. 2754: "Wir bezeichnen diese Substanz als Thymin." (We designate this substance as "thymine" [because it was initially obtained from the thymus glands of calves].)

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

[NASA-20150303-3] Marlaire, Ruth (3 March 2015). "NASA Ames Reproduces the Building Blocks of Life in Laboratory". NASA. Retrieved 5 March 2015.

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案内

5-methyluracil