Selenocysteine

Selenocysteine

Names
IUPAC name 3-Selanyl-2-aminopropanoic acid
Other names L-Selenocysteine; 3-Selanyl-L-alanine; Selenium cysteine
Identifiers
CAS Number	10236-58-5 N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:16633 Y
ChEMBL	ChEMBL109962 Y
ChemSpider	23436 Y
DrugBank	DB02345 Y
ECHA InfoCard	100.236.386
KEGG	C05688 Y
PubChem	25076
UNII	0CH9049VIS N
InChI InChI=1S/C3H7NO2Se/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)/t2-/m0/s1 Y Key: ZKZBPNGNEQAJSX-REOHCLBHSA-N Y InChI=1/C3H7NO2Se/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)/t2-/m0/s1 Key: ZKZBPNGNEQAJSX-REOHCLBHBZ
SMILES O=C(O)[C@@H](N)C[SeH]
Properties
Chemical formula	C3H7NO2Se
Molar mass	168.07 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Selenocysteine (abbreviated as Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid.

Selenocysteine exists naturally in three domains of life, but not in every lineage, as a building block of selenoproteins. Selenocysteine is a cysteine analogue with a selenium-containing selenol group in place of the sulfur-containing thiol group.

Selenocysteine is present in several enzymes (for example glutathione peroxidases, tetraiodothyronine 5' deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine-R-sulfoxide reductase B1 (SEPX1), and some hydrogenases).

Selenocysteine was discovered by biochemist Thressa Stadtman at the National Institutes of Health.

Selenocysteine has a structure similar to that of cysteine, but with an atom of selenium taking the place of the usual sulfur, forming a selenol group which is deprotonated at physiological pH. Proteins that contain one or more selenocysteine residues are called selenoproteins. Most selenoproteins contain a single Sec residue. Selenoproteins with catalytic activities which depend on selenocysteine's biochemical activity are called selenoenzymes. The structurally characterized selenoenzymes have been found to employ catalytic triad structures that influence the nucleophilicity of the active site selenocysteine.