関: phenylthiourea

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/11/10 01:29:17」(JST)

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Phenylthiocarbamide (PTC), also known as phenylthiourea (PTU), is an organosulfur thiourea containing a phenyl ring.

It has the unusual property that it either tastes very bitter or is virtually tasteless, depending on the genetic makeup of the taster. The ability to taste PTC is a dominant genetic trait, and the test to determine PTC sensitivity is one of the most commonly used^{[citation needed]} genetic tests on humans.

PTC also inhibits melanogenesis and is used to grow transparent fish.^[1]

About 70% of people can taste PTC, varying from a low of 58% for indigenous peoples of Australia and New Guinea to 98% for indigenous peoples of the Americas.^[2]^{[dead link]} One study has found that non-smokers and those not habituated to coffee or tea have a statistically higher percentage of tasting PTC than the general population.^[3]^[4] PTC does not occur in food, but related chemicals do, and food choice is related to a person's ability to taste PTC.^[3]^[5] There is conflicting evidence as to whether a higher percentage of women than men can taste PTC.^{[citation needed]}

History

The genetic taste phenomenon of PTC was discovered in 1931 when a DuPont chemist named Arthur Fox accidentally released a cloud of a fine crystalline PTC. A nearby colleague complained about the bitter taste, while Fox, who was closer and should have received a strong dose, tasted nothing. Fox then continued to test the taste buds of assorted family and friends, setting the groundwork for future genetic studies. The genetic correlation was so strong that it was used in paternity tests before the advent of DNA matching.^[6]

In 1976, a remarkable inverse relationship between taster status for PTC and for a bitter component of the fruit of the tree Antidesma bunius was discovered.^[7] Research on the implications still continues.

Some chimpanzees share the ability to taste PTC. However, chimpanzee PTC tasting relies on a different taste receptor than human tasting, suggesting that the ability evolved independently in both species.^[8]

Role in taste

There is a large body of evidence linking the ability to taste thiourea compounds and dietary habits. Much of this work has focused on 6-propyl-2-thiouracil (PROP), a compound related to PTC that has lower toxicity.^[2] A supertaster has more of an ability to taste PTC. On the other hand, heavy cigarette smokers are more likely to have high PTC and PROP thresholds (i.e. are relatively insensitive).

Ability to taste PTC may be correlated with a dislike of plants in the Brassica genus, presumably due to chemical similarities.

Genetics

There are three SNPs (single nucleotide polymorphisms) along the gene that may render its proteins unresponsive.^[9] There is conflicting evidence as to whether the inheritance of this trait is dominant or incomplete dominant.^{[citation needed]} Any person with a single functional copy of this gene can make the protein and is sensitive to PTC.^{[citation needed]} Some studies have shown that homozygous tasters experience a more intense bitterness than people that are heterozygous; other studies have indicated that another gene may determine taste sensitivity.^{[citation needed]}

The frequency of PTC taster and non-taster alleles vary in different human populations.^[10]

Chimpanzees and orang-utans also vary in their ability to taste PTC, with the proportions of tasters and non-tasters similar to that in humans.^[11]

References

^ Karlsson, Johnny; von Hofsten, Jonas; Olsson, Per-Erik (2001). "Generating Transparent Zebrafish: A Refined Method to Improve Detection of Gene Expression During Embryonic Development". Marine Biotechnology 3 (6): 522–527. doi:10.1007/s1012601-0053-4. PMID 14961324.
^ ^a ^b "Question No. 19866". Singapore: Science Centre Singapore. Retrieved 5 December 2009.
^ ^a ^b Fischer, R., Griffin, F. and Kaplan, A. R. (1963). "Taste thresholds, cigarette smoking, and food dislikes". Medicina experimentalis. International journal of experimental medicine 9: 151–67. PMID 14083335.
^ Kaplan AR, Glanville EV, Fischer R (1964). "Taste thresholds for bitterness and cigarette smoking". Nature 202 (4939): 1366. doi:10.1038/2021366a0. PMID 14210998.
^ Forrai G, Bánkövi G (1984). "Taste perception for phenylthiourea and food choice—a Hungarian twin study". Acta Physiol Hung 64 (1): 33–40. PMID 6541419.
^ Lee Phillips M (15 July 2003). "Scientists Find Bitter Taste Gene". Retrieved 5 December 2009.
^ Henkin, R.I. and W.T. Gillis (1977). "Divergent taste responsiveness to fruit of the tree Antidesma bunius". Nature 265 (5594): 536–537. doi:10.1038/265536a0. PMID 834304.
^ Wooding, Stephen; Bufe, Bernd; Grassi, Christina; Howard, Michael T.; Stone, Anne C.; Vazquez, Maribel; Dunn, Diane M.; Meyerhof, Wolfgang et al. (2006). "Independent evolution of bitter-taste sensitivity in humans and chimpanzees". Nature 440 (7086): 930–4. doi:10.1038/nature04655. PMID 16612383.
^ Kim UK, Jorgenson E, Coon H, Leppert M, Risch N, Drayna D (2003). "Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide". Science 299 (5610): 1221–1225. doi:10.1126/science.1080190. PMID 12595690.
^ Fareed, M.; Shah, A.; Hussain, R.; Afzal, M. (2012). "Genetic study of phenylthiocarbamide (PTC) taste perception among six human populations of Jammu and Kashmir (India)". Egypt J Med Hum Genet 13 (2): 161. doi:10.1016/j.ejmhg.2012.01.003.
^ Fisher, Ford and Huxley (1939). Nature 144: 750.

External links

Dennis Drayna's home page. Drayna has done extensive studies of PTC in various populations
Population Study and Applications Using PTC Paper
Classroom activity description using PTC paper
Online 'Mendelian Inheritance in Man' (OMIM) 171200 Thiourea tasting

English Journal

Comparative analysis of goitrogenic effects of phenylthiourea and methimazole in zebrafish embryos.

Fetter E1, Baldauf L2, Da Fonte DF3, Ortmann J2, Scholz S2.
Reproductive toxicology (Elmsford, N.Y.).Reprod Toxicol.2015 Nov;57:10-20. doi: 10.1016/j.reprotox.2015.04.012. Epub 2015 May 8.
Craniofacial malformations, reduced locomotion and induction of genes encoding for enzymes involved in thyroid hormone synthesis were assessed using methimazole and N-phenylthiourea in zebrafish embryos. Gene expression, the most sensitive endpoint (EC50_MMI=372-765μM, EC50_PTU=7.6-8.6μM), was ana
PMID 25962731

Site-specific labeling of synthetic peptide using the chemoselective reaction between N-methoxyamino acid and isothiocyanate.

Hara T1, Purwati EM2, Tainosyo A2, Kawakami T2, Hojo H2, Aimoto S2.
Journal of peptide science : an official publication of the European Peptide Society.J Pept Sci.2015 Oct;21(10):765-9. doi: 10.1002/psc.2803.
Site-specific labeling of synthetic peptides carrying N-methoxyglycine (MeOGly) by isothiocyanate is demonstrated. A nonapeptide having MeOGly at its N-terminus was synthesized by the solid-phase method and reacted with phenylisothiocyanate under various conditions. In acidic solution, the reaction
PMID 26358741

Dual effect of nitric oxide on phenoloxidase-mediated melanization.

Sanzhaeva U1, Vorontsova Y2, Glazachev Y1, Slepneva I1.
Journal of enzyme inhibition and medicinal chemistry.J Enzyme Inhib Med Chem.2015 Sep 25:1-6. [Epub ahead of print]
The study has demonstrated a dual effect of nitric oxide on phenoloxidase (PO)-mediated DOPA oxidation and melanization process. NO generated at low rates proportionally increased in PO-mediated DOPA oxidation. Competitive PO inhibitor, phenylthiourea, resulted in significant inhibition of NO-mediat
PMID 26406272

Japanese Journal

A Case Study on the Association of Variation of Bitter-Taste Receptor Gene TAS2R38 with the Height, Weight and Energy Intake in Japanese Female College Students

INOUE Hiroko,YAMAKAWA-KOBAYASHI Kimiko,SUZUKI Yuichi,NAKANO Teruyo,HAYASHI Hisayoshi,KUWANO Toshiko
Journal of Nutritional Science and Vitaminology 59(1), 16-21, 2013
… Variation of one bitter taste receptor gene, TAS2R38, which is associated with the differential sensitivity to phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), has been demonstrated to affect the dietary intake pattern. …
NAID 130003368144

生息環境に応じた感覚受容体の機能進化

今井啓雄,鈴木南美
生物物理 53(4), 194-197, 2013
In mammals, bitter taste is mediated by TAS2Rs, which belong to the large family of seven transmembrane G protein-coupled receptors. Since TAS2Rs are directly involved in the interaction between mamma …
NAID 130003362500

〔研究ノート〕味盲と味覚受容体発現との関連

岡田友佳,高尾哲也
學苑 842, 36-40, 2010-12-01
… They were tested for whether they could taste phenylthiocarbamide(PTC). …
NAID 110009422466

Related Pictures

★リンクテーブル★

リンク元	「フェニルチオカルバミド」「phenylthiourea」

「フェニルチオカルバミド」

Phenylthiocarbamide
	IUPAC name Phenylthiourea
	Other names N-Phenylthiourea; 1-Phenylthiourea
Identifiers
CAS number	103-85-5
PubChem	676454
UNII	6F82C6Q54C
MeSH	Phenylthiourea
ChEBI	CHEBI:46261
Jmol-3D images	Image 1
	SMILES C1=CC=C(C=C1)NC(=S)N ;
Properties
Molecular formula	C7H8N2S
Molar mass	152.22 g mol−1
Appearance	White to slightly yellow powder
Density	1.294 g/cm3
Melting point	150 °C (302 °F; 423 K)
Solubility in water	Soluble in boiling water
Hazards
EU classification	T+
NFPA 704	1 4 0
LD50	3 mg/kg (oral, rat)
	Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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	Infobox references