“Miraculin”的意思、由来-开放百科全书

Miraculin is a taste modifier, a glycoprotein extracted from the fruit of Synsepalum dulcificum.^[2] The berry, also known as the miracle fruit, was documented by explorer Chevalier des Marchais, who searched for many different fruits during a 1725 excursion to its native West Africa.

Miraculin itself does not taste sweet. When taste buds are exposed to miraculin, the protein binds to the sweetness receptors. This causes normally-sour-tasting acidic foods, such as citrus, to be perceived as sweet.^[2]^[3] The effect lasts up to about an hour.^[5]^[4]

The active substance was named miraculin after its extraction was published in 1968.^[5]

Glycoprotein structure

Miraculin was first sequenced in 1989 and was found to be a 24.6 kilodalton^[2] glycoprotein consisting of 191 amino acids^[6] and 13.9% by weight of various sugars.^[2]

The sugars consist of a total of 3.4 kDa, composed of a molar ratio of glucosamine (31%), mannose (30%), fucose (22%), xylose (10%), and galactose (7%).^[2]

The native state of miraculin is a tetramer consisting of two dimers, each held together by a disulfide bridge.^[8]

Both tetramer miraculin and native dimer miraculin in its crude state have the taste-modifying activity of turning sour tastes into sweet tastes.^[9]

Sweetness properties

Miraculin, unlike curculin (another taste-modifying agent),^[10] is not sweet by itself, but it can change the perception of sourness to sweetness, even for a long period after consumption.^[11] The duration and intensity of the sweetness-modifying effect depends on various factors, such as miraculin concentration, duration of contact of the miraculin with the tongue, and acid concentration.^[3]^[11] Maximum sweet-induced response has been shown to be equivalent to the sweetness of 17% sucrose solution.{{citation needed|date=February 2018}} Glycoprotein is also sensitive to heat. When heated over 100 °C, miraculin loses its taste-modifying property. Miraculin activity is inactivated at pH below 3 and pH above 12 at room temperature.^[11]

Although the detailed mechanism of the taste-inducing behavior is unknown, it appears the sweet receptors are activated by acids which are related to sourness, an effect remaining until the taste buds perceive a neutral pH.^[3]^[11] Sweeteners are perceived by the human sweet taste receptor, hT1R2-hT1R3, which belongs to G protein-coupled receptors,^[11] modified by the two histidine residues (i.e. His30 and His60) which participate in the taste-modifying behavior.^[12] One site maintains the attachment of the protein to the membranes while the other (with attached xylose or arabinose) activates the sweet receptor membrane in acid solutions.^[8]

As a sweetener

As miraculin is a readily soluble protein and relatively heat stable, it is a potential sweetener in acidic food (e.g. soft drinks). While attempts to express it in yeast and tobacco plants have failed, researchers have succeeded in preparing genetically modified E. coli bacteria,^[13] lettuce^[14] and tomatoes^[15] that express miraculin. The scientists' crops resulted in 40 micrograms of miraculin per gram of lettuce leaves, with two grams of lettuce leaves producing roughly the same amount of miraculin as in one miracle fruit berry.^[16]

The use of miraculin as a food additive was forbidden in 1974 by the United States Food and Drug Administration, in circumstances that have been interpreted as suggesting influence by competing commercial interests.^[29]^[17] Since 2011, The FDA has imposed a ban on importing Synsepalum dulcificum (specifying 'miraculin') from its origin in Taiwan, declaring it as an "illegal undeclared sweetener".^[18] Although this ban does not apply to fresh and freeze-dried miracle fruit, the fresh or normally-frozen berry deteriorates rapidly. The ban also does not apply to sale as a dietary supplement.^[19] There is informed opinion that the FDA ban could be overturned given sufficient funding for the required safety studies.^[20] Miraculin has a novel food status in the European Union.^[21] It is approved in Japan as a safe food additive, according to the List of Existing Food Additives published by the Ministry of Health and Welfare (published by JETRO).

See also

References

1. ^{{PDB|3IIR}}; {{cite journal | vauthors = Gahloth D, Selvakumar P, Shee C, Kumar P, Sharma AK | title = Cloning, sequence analysis and crystal structure determination of a miraculin-like protein from Murraya koenigii | journal = Archives of Biochemistry and Biophysics | volume = 494 | issue = 1 | pages = 15–22 | date = February 2010 | pmid = 19914199 | doi = 10.1016/j.abb.2009.11.008 }}
2. ^¹²³⁴{{cite journal | vauthors = Theerasilp S, Kurihara Y | title = Complete purification and characterization of the taste-modifying protein, miraculin, from miracle fruit | journal = The Journal of Biological Chemistry | volume = 263 | issue = 23 | pages = 11536–9 | date = August 1988 | pmid = 3403544 | doi = | url = http://www.jbc.org/cgi/reprint/263/23/11536 }}
3. ^¹²{{cite journal | vauthors = Sanematsu K, Kitagawa M, Yoshida R, Nirasawa S, Shigemura N, Ninomiya Y | title = Intracellular acidification is required for full activation of the sweet taste receptor by miraculin | journal = Scientific Reports | volume = 6 | pages = 22807 | date = March 2016 | pmid = 26960429 | pmc = 4785348 | doi = 10.1038/srep22807 | bibcode = 2016NatSR...622807S }}
4. ^{{cite journal | vauthors = Swamy KB, Hadi SA, Sekaran M, Pichika MR | title = The clinical effects of Synsepalum dulcificum: a review | journal = Journal of Medicinal Food | volume = 17 | issue = 11 | pages = 1165–9 | date = November 2014 | pmid = 25314134 | doi = 10.1089/jmf.2013.3084 }}
5. ^{{cite journal | vauthors = Kurihara K, Beidler LM | title = Taste-modifying protein from miracle fruit | journal = Science | volume = 161 | issue = 3847 | pages = 1241–3 | date = September 1968 | pmid = 5673432 | doi = 10.1126/science.161.3847.1241 | bibcode = 1968Sci...161.1241K }}
6. ^{{cite journal | vauthors = Theerasilp S, Hitotsuya H, Nakajo S, Nakaya K, Nakamura Y, Kurihara Y | title = Complete amino acid sequence and structure characterization of the taste-modifying protein, miraculin | journal = The Journal of Biological Chemistry | volume = 264 | issue = 12 | pages = 6655–9 | date = April 1989 | pmid = 2708331 | doi = | url = http://www.jbc.org/cgi/reprint/264/12/6655 }}
7. ^UniProtKB/Swiss-Prot database entry P13087
8. ^¹{{cite journal | vauthors = Kurihara Y | title = Characteristics of antisweet substances, sweet proteins, and sweetness-inducing proteins | journal = Critical Reviews in Food Science and Nutrition | volume = 32 | issue = 3 | pages = 231–52 | year = 1992 | pmid = 1418601 | doi = 10.1080/10408399209527598 }}
9. ^{{cite journal | vauthors = Igeta H, Tamura Y, Nakaya K, Nakamura Y, Kurihara Y | title = Determination of disulfide array and subunit structure of taste-modifying protein, miraculin | journal = Biochimica et Biophysica Acta | volume = 1079 | issue = 3 | pages = 303–7 | date = September 1991 | pmid = 1911854 | doi = 10.1016/0167-4838(91)90073-9 }}
10. ^{{cite journal | vauthors = Kurimoto E, Suzuki M, Amemiya E, Yamaguchi Y, Nirasawa S, Shimba N, Xu N, Kashiwagi T, Kawai M, Suzuki E, Kato K | title = Curculin exhibits sweet-tasting and taste-modifying activities through its distinct molecular surfaces | journal = The Journal of Biological Chemistry | volume = 282 | issue = 46 | pages = 33252–6 | date = November 2007 | pmid = 17895249 | doi = 10.1074/jbc.C700174200 }}
11. ^¹²³⁴⁵{{cite journal | vauthors = Koizumi A, Tsuchiya A, Nakajima K, Ito K, Terada T, Shimizu-Ibuka A, Briand L, Asakura T, Misaka T, Abe K | title = Human sweet taste receptor mediates acid-induced sweetness of miraculin | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 108 | issue = 40 | pages = 16819–24 | date = October 2011 | pmid = 21949380 | pmc = 3189030 | doi = 10.1073/pnas.1016644108 | bibcode = 2011PNAS..10816819K }}
12. ^{{cite journal | vauthors = Ito K, Asakura T, Morita Y, Nakajima K, Koizumi A, Shimizu-Ibuka A, Masuda K, Ishiguro M, Terada T, Maruyama J, Kitamoto K, Misaka T, Abe K | title = Microbial production of sensory-active miraculin | journal = Biochemical and Biophysical Research Communications | volume = 360 | issue = 2 | pages = 407–11 | date = August 2007 | pmid = 17592723 | doi = 10.1016/j.bbrc.2007.06.064 }}
13. ^{{cite journal | vauthors = Matsuyama T, Satoh M, Nakata R, Aoyama T, Inoue H | title = Functional expression of miraculin, a taste-modifying protein in Escherichia coli | journal = Journal of Biochemistry | volume = 145 | issue = 4 | pages = 445–50 | date = April 2009 | pmid = 19122203 | doi = 10.1093/jb/mvn184 }}
14. ^{{cite journal | vauthors = Sun HJ, Cui ML, Ma B, Ezura H | title = Functional expression of the taste-modifying protein, miraculin, in transgenic lettuce | journal = FEBS Letters | volume = 580 | issue = 2 | pages = 620–6 | date = January 2006 | pmid = 16406368 | doi = 10.1016/j.febslet.2005.12.080 }}
15. ^{{cite journal | vauthors = Kato K, Yoshida R, Kikuzaki A, Hirai T, Kuroda H, Hiwasa-Tanase K, Takane K, Ezura H, Mizoguchi T | title = Molecular breeding of tomato lines for mass production of miraculin in a plant factory | journal = Journal of Agricultural and Food Chemistry | volume = 58 | issue = 17 | pages = 9505–10 | date = September 2010 | pmid = 20695489 | doi = 10.1021/jf101874b }}
16. ^{{cite news |first=Joanna |last=Slater | name-list-format = vanc |title=To Make Lemons Into Lemonade, Try 'Miracle Fruit' |url=https://www.wsj.com/articles/SB117522147769754148 |publisher=Wall Street Journal |date=2007-03-30 |access-date=2008-05-28 |quote=[...]two grams produce roughly the same effect as one miracle fruit. }}
17. ^{{cite book | first = Adam Leith | last = Gollner | name-list-format = vanc | title = The Fruit Hunters: A Story of Nature, Adventure, Commerce and Obsession | isbn = 978-0385662680 | publisher = Anchor Canada | date = 31 March 2009 }}
18. ^{{cite web|title=Synsepalum dulcificum Import Alert 45-07; Taiwan|url=https://www.accessdata.fda.gov/cms_ia/importalert_120.html|publisher=US Food and Drug Administration|access-date=9 February 2018|date=5 February 2018}}
19. ^{{cite news |first=Brian |last=Hieggelke | name-list-format = vanc |title=Sugar Freedom: Chef Homaro Cantu and his Magnificent Miracle Berry Obsession |url=https://resto.newcity.com/2013/04/18/sugar-freedom-chef-homaro-cantu-and-his-magnificent-miracle-berry-obsession/ |publisher=NewCity Communications Inc. |date=2013-04-18 |access-date=2018-02-25}}
20. ^¹{{cite news |first=David |last=Cox | name-list-format = vanc |title=The 'Miracle' Berry That Could Replace Sugar|url=https://www.theatlantic.com/health/archive/2014/05/can-miraculin-solve-the-global-obesity-epidemic/371657/ |publisher=The Atlantic Monthly Group |date=2014-05-29 |access-date=2018-02-25}}
21. ^{{cite web|title=Novel Food Catalogue |url= http://ec.europa.eu/food/food/biotechnology/novelfood/nfnetweb/mod_search/index.cfm?action=mod_search.details&seqfce=464 |access-date=2 July 2013}}