Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a
biomolecule
A biomolecule or biological molecule is loosely defined as a molecule produced by a living organism and essential to one or more typically biological processes. Biomolecules include large macromolecules such as proteins, carbohydrates, lipids ...
produced from
riboflavin
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...
(vitamin B
2) by the enzyme
riboflavin kinase and functions as the
prosthetic group
A prosthetic group is the non-amino acid component that is part of the structure of the heteroproteins or conjugated proteins, being tightly linked to the apoprotein.
Not to be confused with the cosubstrate that binds to the enzyme apoenzyme (e ...
of various
oxidoreductases, including
NADH dehydrogenase, as well as a
cofactor in biological blue-light photo receptors. During the catalytic cycle, various
oxidoreductases induce reversible interconversions between the oxidized (FMN), semiquinone (FMNH
•), and reduced (FMNH
2) forms of the
isoalloxazine core. FMN is a stronger oxidizing agent than
NAD and is particularly useful because it can take part in both one- and two-electron transfers. In its role as blue-light photo receptor, (oxidized) FMN stands out from the 'conventional' photo receptors as the signaling state and not an E/Z isomerization.
It is the principal form in which riboflavin is found in
cells and
tissues. It requires more energy to produce, but is more
soluble than riboflavin. In cells, FMN occurs freely circulating but also in several
covalently bound forms.
Covalently or non-covalently bound FMN is a cofactor of many enzymes playing an important pathophysiological role in cellular metabolism. For example dissociation of flavin mononucleotide from mitochondrial complex I has been shown to occur during ischemia/reperfusion brain injury during stroke.
Food additive
Flavin mononucleotide is also used as an orange-red food colour additive, designated in Europe as
E number
E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...
E101a.
E106, a very closely related food dye, is riboflavin-5′-phosphate sodium salt, which consists mainly of the
monosodium salt
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
of the 5′-monophosphate
ester
In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...
of riboflavin. It is rapidly turned to free riboflavin after
ingestion. It is found in many foods for babies and young children as well as
jams,
milk
Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...
products, and sweets and
sugar
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...
products.
See also
*
Flavin adenine dinucleotide
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which ma ...
References
External links
FMNin th
EBI Macromolecular Structure Database
{{Enzyme cofactors
Flavins
Food colorings
Organophosphates
Oxidoreductases
Cofactors