Miraculin glycoprotein | |||||||
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Identifiers | |||||||
Organism | |||||||
Symbol | MIRA_RICDU | ||||||
PDB | 3IIR | ||||||
UniProt | P13087 | ||||||
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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 can last for one or two hours. [4] [5]
The sweetening properties of Synsepalum dulcificum berries were first noted by des Marchais during expeditions to West Africa in the 18th century. [6] The term miraculin derived from experiments to isolate and purify the active glycoprotein that gave the berries their sweetening effects, results that were published simultaneously by Japanese and Dutch scientists working independently in the 1960s (the Dutch team called the glycoprotein mieraculin). [7] [8] The word miraculin was in common use by the mid-1970s. [9] [10] [11]
Miraculin was first sequenced in 1989 and was found to be a 24.6 kilodalton [2] glycoprotein consisting of 191 amino acids [12] and 13.9% by weight of various sugars. [2]
SIGNAL (29) M K E L TMLSLS FFFVSALLAA AAN PLLSAA 1–50 DSAPNPVLDI DGEKLRTGTN YYIVPVLRDH GGGLTVSATT PNGTFVCPPR 51–100 VVQTRKEVDH DRPLAFFPEN PKEDVVRVST DLNINFSAFM PNPGPETISS 101–150 WCRWTSSTVW RLDKYDESTG QYFVTIGGVK FKIEEFCGSG FYKLVFCPTV 151–191 CGSCKVKCGD VGIYIDQKGR GRRLALSDKP FAFEFNKTVY F Amino acids sequence of glycoprotein miraculin unit adapted from Swiss-Prot biological database of protein sequences. [13]
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. [14] Both tetramer miraculin and native dimer miraculin in its crude state have the taste-modifying activity of turning sour tastes into sweet tastes. [15] Miraculin belongs to the Kunitz STI protease inhibitor family.
Miraculin, unlike curculin (another taste-modifying agent), [16] is not sweet by itself, but it can change the perception of sourness to sweetness, even for a long period after consumption. [4] 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] [4] Miraculin reaches its maximum sweetness with a solution containing at least 4*10−7 mol/L miraculin, which is held in the mouth for about 3 minutes. Maximum is equivalent in sweetness to a 0.4 mol/L solution of sucrose. [17] Miraculin degrades permanently via denaturation at high temperatures and at pH below 3 or above 12. [18]
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] [4] Sweeteners are perceived by the human sweet taste receptor, hT1R2-hT1R3, which belongs to G protein-coupled receptors, [4] modified by the two histidine residues (i.e. His30 and His60) which participate in the taste-modifying behavior. [19] 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. [14]
As miraculin is a readily soluble protein and relatively heat stable, it is a potential sweetener in acidic food, such as soft drinks. While attempts to express it in yeast and tobacco plants have failed, researchers have succeeded in preparing genetically modified E. coli bacteria that express miraculin. [20] Lettuce and tomato have also been used for mass production of miraculin. [21] [22]
The use of miraculin as a food additive was denied in 1974 by the United States Food and Drug Administration. [23] However, it can still be sold in the form of whole berries or tablets (as "dietary supplements"). [24] [25] In 2011 the FDA banned a certain brand of miraculin tablets imported from Taiwan as it was thought to be "hard candy" with non-approved sweeteners. [26] Miraculin has a novel food status in the European Union. [27] 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 the Japan External Trade Organization).
Umami, or savoriness, is one of the five basic tastes. It is characteristic of broths and cooked meats.
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated.
Thaumatin is a low-calorie sweetener and taste modifier. The protein is often used primarily for its flavor-modifying properties and not exclusively as a sweetener.
Monellin, a sweet protein, was discovered in 1969 in the fruit of the West African shrub known as serendipity berry ; it was first reported as a carbohydrate. The protein was named in 1972 after the Monell Chemical Senses Center in Philadelphia, U.S.A., where it was isolated and characterized.
Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones, and sugar alcohols. Some are sweet at very low concentrations, allowing their use as non-caloric sugar substitutes. Such non-sugar sweeteners include saccharin, aspartame, sucralose and stevia. Other compounds, such as miraculin, may alter perception of sweetness itself.
Gymnema sylvestre is a perennial woody vine native to Asia, Africa and Australia. It has been used in Ayurvedic medicine. Common names include gymnema, Australian cowplant, and Periploca of the woods, and the Hindi term gurmar, which means "sugar destroyer".
Synsepalum dulcificum is a plant in the Sapotaceae family, native to tropical Africa. It is known for its berry that, when eaten, causes sour foods subsequently consumed to taste sweet. This effect is due to miraculin. Common names for this species and its berry include miracle fruit, miracle berry, miraculous berry, sweet berry, and in West Africa, where the species originates, àgbáyun, taami, asaa, and ledidi.
Aftertaste is the taste intensity of a food or beverage that is perceived immediately after that food or beverage is removed from the mouth. The aftertastes of different foods and beverages can vary by intensity and over time, but the unifying feature of aftertaste is that it is perceived after a food or beverage is either swallowed or spat out. The neurobiological mechanisms of taste signal transduction from the taste receptors in the mouth to the brain have not yet been fully understood. However, the primary taste processing area located in the insula has been observed to be involved in aftertaste perception.
Brazzein is a protein found in the West African fruit of Oubli. It was first isolated by the University of Wisconsin–Madison in 1994.
A taste receptor or tastant is a type of cellular receptor that facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations. Molecules which give a sensation of taste are considered "sapid".
Curculin or neoculin is a sweet protein that was discovered and isolated in 1990 from the fruit of Curculigo latifolia (Hypoxidaceae). Like miraculin, curculin exhibits taste-modifying activity; however, unlike miraculin, it also exhibits a sweet taste by itself. After consumption of curculin, water and sour solutions taste sweet.
Ziziphin, a triterpene glycoside which exhibits taste-modifying properties, has been isolated from the leaves of Ziziphus jujuba (Rhamnaceae).
Pentadin, a sweet-tasting protein, was discovered and isolated in 1989, in the fruit of oubli, a climbing shrub growing in some tropical countries of Africa. Sweet tasting proteins are often used in the treatment of diabetes, obesity, and other metabolic disorders that one can experience. These proteins are isolated from the pulp of various fruits, typically found in rain forests and are also used as low calorie sweeteners that can enhance and modify existing foods.
Mabinlins are sweet-tasting proteins extracted from the seed of mabinlang, a plant growing in Yunnan province of China. There are four homologues. Mabinlin-2 was first isolated in 1983 and characterised in 1993, and is the most extensively studied of the four. The other variants of mabinlin-1, -3 and -4 were discovered and characterised in 1994.
Free fatty acid receptor 1 (FFAR1), also known as G-protein coupled receptor 40 (GPR40), is a rhodopsin-like G-protein coupled receptor that is coded by the FFAR1 gene. This gene is located on the short arm of chromosome 19 at position 13.12. G protein-coupled receptors reside on their parent cells' surface membranes, bind any one of the specific set of ligands that they recognize, and thereby are activated to trigger certain responses in their parent cells. FFAR1 is a member of a small family of structurally and functionally related GPRs termed free fatty acid receptors (FFARs). This family includes at least three other FFARs viz., FFAR2, FFAR3, and FFAR4. FFARs bind and thereby are activated by certain fatty acids.
Taste receptor type 1 member 3 is a protein that in humans is encoded by the TAS1R3 gene. The TAS1R3 gene encodes the human homolog of mouse Sac taste receptor, a major determinant of differences between sweet-sensitive and -insensitive mouse strains in their responsiveness to sucrose, saccharin, and other sweeteners.
Gurmarin is a 35-residue polypeptide from the Asclepiad vine Gymnema sylvestre (Gurmar). It has been utilized as a pharmacological tool in the study of sweet-taste transduction because of its ability to selectively inhibit the neural response to sweet taste in rats. This rat inhibition appears to have high specificity to sugar (sweetener) molecules like sucrose, glucose, and saccharin as well as the amino acid glycine. As a sweet-taste-suppressing protein, Gurmarin shows signs of being reversible in nature although having little to no effect on the sweet taste sensation in humans suggesting the protein is only active on rodent sweet taste receptors.
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with the sense of smell and trigeminal nerve stimulation, determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas, including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste.
Magical fruit may refer to:
Curculigo is a flowering plant genus in the family Hypoxidaceae, first described in 1788. It is widespread across tropical regions of Asia, Africa, Australia, and the Americas.