Selenoneine is a
selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and telluriu ...
containing
ergothioneine
Ergothioneine is a naturally occurring amino acid and is a thiourea derivative of histidine, containing a sulfur atom on the imidazole ring. This compound occurs in relatively few organisms, notably actinomycetota, cyanobacteria, and certain fun ...
derivative where the selenium (Se) atom replaces a sulfur atom. It can be systematically named as (2-selenyl-N
α,N
α,N
α-trimethyl-L-histidine or 3-(2-hydroseleno-1H-imidazol-5-yl)-2-(trimethylammonio)propanoate).
It is found in the blood of
bluefin tuna Bluefin tuna is a common name used to refer to several species of tuna of the genus '' Thunnus''.
{{Animal common name
Commercial fish
Thunnus
Fish common names ...
, and other sea dwelling animals like turtles, mackerel,
beluga The beluga whale (/bɪˈluːɡə/) (Delphinapterus leucas) is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus Delphinapterus. It is also known as the wh ...
, and
giant petrel
Giant petrels form a genus, ''Macronectes'', from the family Procellariidae, which consists of two species. They are the largest birds of this family. Both species are restricted to the Southern Hemisphere, and though their distributions overlap ...
s.
It is an antioxidant,
[ combining with ]reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen ...
and boosting the action of GPx1
Glutathione peroxidase 1, also known as GPx1, is an enzyme that in humans is encoded by the ''GPX1'' gene on chromosome 3. This gene encodes a member of the glutathione peroxidase family. Glutathione peroxidase functions in the detoxification of h ...
.
Selenoneine is produced by microorganisms using enzymes that form a selenium-carbon bond. Humans that eat fish have selenoneine in their blood. About half of selenium is in the form of selenoneine. Selenoneine inhibits angiotensin-converting enzyme
Angiotensin-converting enzyme (), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstr ...
. In vertebrates, selenoneine is transported into cells using OCTN1
Solute carrier family 22, member 4, also known as SLC22A4, is a human gene; the encoded protein is known as the ergothioneine transporter.
Function
The encoded protein is an integral protein of the plasma membrane containing 12 transmembrane se ...
.[ Selenoneine reacts with ]methyl mercury
Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula . It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is ...
to form a mercury tetraselenoate complex, which degrades to tiemannite
Tiemannite is a mineral, mercury selenide, formula HgSe. It occurs in hydrothermal veins associated with other selenides, or other mercury minerals such as cinnabar, and often with calcite. Discovered in 1855 in Germany, it is named after Joha ...
, a mercury selenide
Mercury selenide (HgSe; sometimes mercury(II) selenide) is a chemical compound of mercury and selenium. It is a grey-black crystalline solid semi-metal with a sphalerite structure. The lattice constant is 0.608 nm.
HgSe occurs naturally ...
. This is a mechanism used to detoxify mercury in marine vertebrates.[ A related derivative, Se-methylselenoneine is found in lesser quantities in mackerel, sardine and tuna.]
References
{{Reflist
Selenols
Quaternary ammonium compounds
Imidazolines
Amino acids