Selenoneine

Selenoneine is a selenium containing ergothioneine 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).

Selenoneine

Identifiers
3D model (JSmol)	Interactive image selenol tautomer: Interactive image
ChEBI	CHEBI:79071
ChemSpider	34449139
PubChem CID	selenol tautomer: 86289064
InChI InChI=1S/C9H15N3O2Se/c1-12(2,3)7(8(13)14)4-6-5-10-9(15)11-6/h5,7H,4H2,1-3H3,(H2-,10,11,13,14,15)/t7-/m0/s1 Key: MTIQLELFQVCRSW-ZETCQYMHSA-N selenol tautomer: InChI=1S/C9H14N3O2Se/c1-12(2,3)7(8(13)14)4-6-5-10-9(15)11-6/h5,7H,4H2,1-3H3,(H-,10,11,13,14)/t7-/m0/s1 Key: FONQTPPQNMLDTP-ZETCQYMHSA-N
SMILES C[N+](C)(C)[C@@H](Cc1c[nH][c](=[Se])[nH]1)C([O-])=O selenol tautomer: C[N+](C)(C)[C@@H](CC1=CN=C(N1)[Se])C(=O)[O-]
Properties
Chemical formula	C9H14N3O2Se
Molar mass	275.201 g·mol−1
Related compounds
Related compounds	Selenocysteine; Ergothioneine; Histidine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

It is found in the blood of bluefin tuna,^[1][2] and other sea dwelling animals like turtles, mackerel, beluga,^[3] and giant petrels.^[4] It is an antioxidant,^[5] combining with reactive oxygen species and boosting the action of GPx1.^[6]

Selenoneine is produced by microorganisms using enzymes that form a selenium-carbon bond.^[7] Humans that eat fish have selenoneine in their blood. About half of selenium is in the form of selenoneine.^{[8] [9]} Selenoneine inhibits angiotensin-converting enzyme.^[10] In vertebrates, selenoneine is transported into cells using OCTN1.^[4] Selenoneine reacts with methyl mercury to form a mercury tetraselenoate complex, which degrades to tiemannite, a mercury selenide. This is a mechanism used to detoxify mercury in marine vertebrates.^[4] A related derivative, Se-methylselenoneine is found in lesser quantities in mackerel, sardine and tuna.^[11]

In air selenoneine is easily oxidised to a dimer containing a diselenide bond (Se-Se).^[5]