Brazzein
Encyclopedia
Brazzein is a sweet-tasting protein
extracted from the West African fruit of the climbing plant Oubli (Pentadiplandra brazzeana
Baillon
). It was first isolated as an enzyme
by University of Wisconsin–Madison
in 1994.
Brazzein is found in the extracellular region. The tissue it's found in is the pulp surrounding the seeds.
With pentadin
, discovered in 1989, brazzein is the second sweet-tasting protein discovered in this African fruit.
Like the other natural sweet-proteins such as monellin
and thaumatin
, it is highly sweet.
and Cameroon
, where the fruit has been consumed by the apes and local people for a long time. The berries of the plant are incredibly sweet. African locals call them "Oubli" (French for "forgot") in their vernacular language because their taste helps nursing infants forget their mother's milk, as once they eat them they forget to come back to the village to see their mother.
. The amino acid sequence of brazzein, adapted from the Swiss-Prot biological database of protein, is as follows: QDKCKKVYEN YPVSKCQLAN QCNYDCKLDK HARSGECFYD EKRNLQCICD YCEY
The structure of brazzein was determined by proton nuclear magnetic resonance
(NMR) at a pH 5.2 and 22 degrees C.. Brazzein has four evenly spaced disulfide bonds and no sulfhydryl groups.
3D analysis of brazzein showed one alpha-helix and three strands of anti-parallel beta sheet
. It is not similar to either of the other two sweet-tasting proteins, monellin
and thaumatin
.
However, a recent 3D study shows that these three proteins possess similar "sweet fingers" believed to elicit the sweet taste.
Residues 29–33 and 39–43, plus residue 36, as well as the C-terminus were found to be involved in the sweet tasting of the protein. The charge of the protein plays also an important role in its interaction with the sweet taste receptor
.
Based on this knowledge a synthesised improved brazzein, called pGlu-1-brazzein, was reported to be twice sweet as the natural counterpart.
Its sweet perception is more similar to sucrose than that of thaumatin with a clean sweet taste with lingering aftertaste and with a slight delay longer than aspartame in an equi-sweet solution.
Brazzein is stable over a broad pH range from 2.5 to 8 and heat stable at 98°C for 2 hours.
s. As a protein it is safe for diabetics and very soluble in water (>50 mg/mL).
When blended with other sweeteners, sweeteners such as aspartame
and stevia
, brazzein reduces side aftertaste and complements their flavor.
Unlike other natural sweeteners, apart from thaumatin
, its sweet profile is closer to sucrose. Unlike other sweet-tasting proteins, it can withstand heat which make it suitable for any industrial food manufacture.
Increasing interest of brazzein makes it difficult to source naturally from Gabon, but it can also be synthesised by a solid-phase method.
Recombinant proteins were successfully produced via E. coli
.
The Texas companies Prodigene and Nectar Worldwide were among the licensees to use Wisconsin Alumni Research Foundation patents on brazzein, and genetically engineer the enzyme into maize. Brazzein then can be commercially extracted from maize through ordinary milling. Approximately one ton of maize yields 1-2 kilograms of Brazzein. It can also be engineered into plants like wheat to make pre-sweetened grains, e.g. for cereals.
Natur Research Ingredients intends to market brazzein under the Cweet (1000x) and (3000x) brands by 2009.
This fact, which involved appropriation of legal rights by means of patents over indigenous biomedical knowledge without compensation to the indigenous groups, is considered an act of Biopiracy
by GRAIN
and Green Peace.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
extracted from the West African fruit of the climbing plant Oubli (Pentadiplandra brazzeana
Pentadiplandra brazzeana
Pentadiplandra brazzeana is the sole species in the plant genus Pentadiplandra, which is placed alone in family Pentadiplandraceae....
Baillon
Henri Ernest Baillon
Henri Ernest Baillon was a French botanist and physician. He was born in Calais on November 30, 1827 and died in Paris on July 19, 1895.Baillon spent his professional life as a professor of natural history, and he published numerous works on botany...
). It was first isolated as an enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
by University of Wisconsin–Madison
University of Wisconsin–Madison
The University of Wisconsin–Madison is a public research university located in Madison, Wisconsin, United States. Founded in 1848, UW–Madison is the flagship campus of the University of Wisconsin System. It became a land-grant institution in 1866...
in 1994.
Brazzein is found in the extracellular region. The tissue it's found in is the pulp surrounding the seeds.
With pentadin
Pentadin
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....
, discovered in 1989, brazzein is the second sweet-tasting protein discovered in this African fruit.
Like the other natural sweet-proteins such as monellin
Monellin
Monellin is a sweet protein which was discovered in 1969 in the fruit of the West African shrub known as serendipity berry , it was first reported as a carbohydrate...
and thaumatin
Thaumatin
Thaumatin is a low-calorie sweetener and flavour modifier. The substance, a natural protein, is often used primarily for its flavour-modifying properties and not exclusively as a sweetener....
, it is highly sweet.
Traditional use
The plant grows in GabonGabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...
and Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...
, where the fruit has been consumed by the apes and local people for a long time. The berries of the plant are incredibly sweet. African locals call them "Oubli" (French for "forgot") in their vernacular language because their taste helps nursing infants forget their mother's milk, as once they eat them they forget to come back to the village to see their mother.
Protein structure
The monomer protein, consisting of 54 amino acid residues, is the smallest of the sweet proteins with a molecular weigh of 6.5 kDaAtomic mass unit
The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...
. The amino acid sequence of brazzein, adapted from the Swiss-Prot biological database of protein, is as follows: QDKCKKVYEN YPVSKCQLAN QCNYDCKLDK HARSGECFYD EKRNLQCICD YCEY
The structure of brazzein was determined by proton nuclear magnetic resonance
Nuclear magnetic resonance
Nuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
(NMR) at a pH 5.2 and 22 degrees C.. Brazzein has four evenly spaced disulfide bonds and no sulfhydryl groups.
3D analysis of brazzein showed one alpha-helix and three strands of anti-parallel beta sheet
Beta sheet
The β sheet is the second form of regular secondary structure in proteins, only somewhat less common than the alpha helix. Beta sheets consist of beta strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet...
. It is not similar to either of the other two sweet-tasting proteins, monellin
Monellin
Monellin is a sweet protein which was discovered in 1969 in the fruit of the West African shrub known as serendipity berry , it was first reported as a carbohydrate...
and thaumatin
Thaumatin
Thaumatin is a low-calorie sweetener and flavour modifier. The substance, a natural protein, is often used primarily for its flavour-modifying properties and not exclusively as a sweetener....
.
However, a recent 3D study shows that these three proteins possess similar "sweet fingers" believed to elicit the sweet taste.
Residues 29–33 and 39–43, plus residue 36, as well as the C-terminus were found to be involved in the sweet tasting of the protein. The charge of the protein plays also an important role in its interaction with the sweet taste receptor
Taste receptor
A Taste receptor is a type of receptor which facilitates the sensation of taste.Examples include TAS2R16 and TAS2R38.They are divided into two families:* Type 1, sweet, first characterized in 2001: –...
.
Based on this knowledge a synthesised improved brazzein, called pGlu-1-brazzein, was reported to be twice sweet as the natural counterpart.
Sweetness properties
On weight basis, brazzein is 500 to 2000 times sweeter than sugar, compared to 10% sugar and 2% sugar solution respectively.Its sweet perception is more similar to sucrose than that of thaumatin with a clean sweet taste with lingering aftertaste and with a slight delay longer than aspartame in an equi-sweet solution.
Brazzein is stable over a broad pH range from 2.5 to 8 and heat stable at 98°C for 2 hours.
As a sweetener
Brazzein represents an alternative to available low calorie sweetenerSugar substitute
A sugar substitute is a food additive that duplicates the effect of sugar in taste, usually with less food energy. Some sugar substitutes are natural and some are synthetic. Those that are not natural are, in general, called artificial sweeteners....
s. As a protein it is safe for diabetics and very soluble in water (>50 mg/mL).
When blended with other sweeteners, sweeteners such as aspartame
Aspartame
Aspartame is an artificial, non-saccharide sweetener used as a sugar substitute in some foods and beverages. In the European Union, it is codified as E951. Aspartame is a methyl ester of the aspartic acid/phenylalanine dipeptide. It was first sold under the brand name NutraSweet; since 2009 it...
and stevia
Stevia
Stevia is a genus of about 240 species of herbs and shrubs in the sunflower family , native to subtropical and tropical regions from western North America to South America. The species Stevia rebaudiana, commonly known as sweetleaf, sweet leaf, sugarleaf, or simply stevia, is widely grown for its...
, brazzein reduces side aftertaste and complements their flavor.
Unlike other natural sweeteners, apart from thaumatin
Thaumatin
Thaumatin is a low-calorie sweetener and flavour modifier. The substance, a natural protein, is often used primarily for its flavour-modifying properties and not exclusively as a sweetener....
, its sweet profile is closer to sucrose. Unlike other sweet-tasting proteins, it can withstand heat which make it suitable for any industrial food manufacture.
Increasing interest of brazzein makes it difficult to source naturally from Gabon, but it can also be synthesised by a solid-phase method.
Recombinant proteins were successfully produced via E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
.
The Texas companies Prodigene and Nectar Worldwide were among the licensees to use Wisconsin Alumni Research Foundation patents on brazzein, and genetically engineer the enzyme into maize. Brazzein then can be commercially extracted from maize through ordinary milling. Approximately one ton of maize yields 1-2 kilograms of Brazzein. It can also be engineered into plants like wheat to make pre-sweetened grains, e.g. for cereals.
Natur Research Ingredients intends to market brazzein under the Cweet (1000x) and (3000x) brands by 2009.
Brazzein controversy
Despite the fact that the sweet taste of the berries was well known in West Africa, the University claims that the sweet compound (brazzein) is its own invention and admit to no connection with the Gabon.This fact, which involved appropriation of legal rights by means of patents over indigenous biomedical knowledge without compensation to the indigenous groups, is considered an act of Biopiracy
Biopiracy
- Biopiracy and bioprospecting :Bioprospecting is an umbrella term describing the discovery of new and useful biological samples and mechanisms, typically in less-developed countries, either with or without the help of indigenous knowledge, and with or without compensation...
by GRAIN
GRAIN
GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...
and Green Peace.