Tellurocysteine

Tellurocysteine

Names
IUPAC name (2R)-2-Amino-3-tellanylpropanoic acid
Other names Tellurocystine
Identifiers
3D model (JSmol)	Interactive image
ChemSpider	34500822
PubChem CID	129631934
InChI InChI=1S/C3H7NO2Te/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6) Key: PRMLZSRTFWAUAH-UHFFFAOYSA-N
SMILES C(C(C(=O)O)N)[TeH]
Properties
Chemical formula	C3H7NO2Te
Molar mass	216.69 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tellurocysteine (in some publications referred to as Te-Cys) is an amino acid analogous to serine, cysteine and selenocysteine with tellurium in place of oxygen, sulfur or selenium in its side chain. It is not naturally found in organisms.

Properties[]

Perhaps due to its low bond energy with carbon (200 kJ/mol compared to 234 kJ/mol for selenium, or 272 kJ/mol for sulfur),^[1] tellurocysteine is not present in any known natural organisms and is hence relatively understudied in comparison to selenocysteine.^[2] Despite so, certain organisms such as fungi Aspergillus fumigatus is capable of incorporating tellurocysteine and telluromethionine into amino acids and proteins when exposed to a sulfur-free environment.^[3]

It has been observed that when incorporated into glutathione transferase, tellurocysteine efficiently inhibited aminoacylation and increased the efficiency of glutathione peroxidase.^[4]

Synthesis[]

L-Tellurocysteine has been prepared from elemental tellurium by first reacting it with methyl (2R)-2-[(tert-butoxycarbonyl)amino]-3-iodopropionate in a tetrahydrofuran solvent with presence of lithium triethylborohydride, yielding a red oil which is acidified and treated with alkali before a treatment with citric acid to set its pH to 4.0, resulting in an orange solid after filtering and drying.^[5]

References[]