Tellurocysteine

Tellurocysteine
Names
	IUPAC name (2R)-2-Amino-3-tellanylpropanoic acid
	Other names Tellurocystine
Identifiers
CAS Number	122096-31-5 ;
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@@H](C(=O)O)N)[Te];
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 with the formula HTeCH₂CH(NH₂)CO₂H. It is the heavy analogue of serine, cysteine, and selenocysteine. Tellurol (RTeH) is a rare and fragile functional group, especially alkyl derivatives. The C-Te bond (200 kJ/mol) is weak compared to 234 kJ/mol for the C-Se bond.^[1] These factors combine to make tellurocysteine very labile. Even selenocysteine occurs only rarely in nature.^[2] Instead of tellurocysteine, tellurocystine is generally isolated instead. Tellurocystine has the formula (TeCH₂CH(NH₂)CO₂H)₂, with a central Te-Te bond.^[3]

Properties

The fungus Aspergillus fumigatus is capable of incorporating tellurocysteine (and telluromethionine) into proteins when grown in appropriate media.^[4]

When incorporated into glutathione transferase, tellurocysteine efficiently inhibits aminoacylation and increases the efficiency of glutathione peroxidase.^[5]

Synthesis

Structure of L-tellurocystine.

L-Tellurocystine has been prepared in low yield from a protected form of 3-iodoalanine. Thus, methyl (2R)-2-[(tert-butoxycarbonyl)amino]-3-iodopropionate reacts with lithium telluride to produce tellurocystine.^[3]

References

^ Chivers, Tristram; Laitinen, Risto S. (23 March 2015). "Tellurium: a maverick among the chalcogens". Chemical Society Reviews. 44 (7): 1725–1739. doi:10.1039/C4CS00434E. ISSN 1460-4744. PMID 25692398.
^ Advances in Microbial Physiology. Academic Press. 2007. p. 4. ISBN 9780080560649.
^ ^a ^b Stocking, Emily M.; Schwarz, Jessie N.; Senn, Hans; Salzmann, Michael; Silks, Louis A. (1 January 1997). "Synthesis of L-selenocystine,L-[77Se]selenocystine and L-tellurocystine". Journal of the Chemical Society, Perkin Transactions 1 (16): 2443–2448. doi:10.1039/A600180G. ISSN 1364-5463.
^ Ramadan, ShadiaE.; Razak, A.A.; Ragab, A.M.; El-Meleigy, M. (1 June 1989). "Incorporation of tellurium into amino acids and proteins in a tellurium-tolerant fungi". Biological Trace Element Research. 20 (3): 225–232. Bibcode:1989BTER...20..225R. doi:10.1007/BF02917437. ISSN 0163-4984. PMID 2484755. S2CID 9439946.
^ Liu, Xiaoman; Silks, Louis A.; Liu, Cuiping; Ollivault-Shiflett, Morgane; Huang, Xin; Li, Jing; Luo, Guimin; Hou, Ya-Ming; Liu, Junqiu; Shen, Jiacong (2 March 2009). "Incorporation of Tellurocysteine into Glutathione Transferase Generates High Glutathione Peroxidase Efficiency". Angewandte Chemie International Edition. 48 (11): 2020–2023. doi:10.1002/anie.200805365. PMID 19199319.

[1] Chivers, Tristram; Laitinen, Risto S. (23 March 2015). "Tellurium: a maverick among the chalcogens". Chemical Society Reviews. 44 (7): 1725–1739. doi:10.1039/C4CS00434E. ISSN 1460-4744. PMID 25692398.

[2] Advances in Microbial Physiology. Academic Press. 2007. p. 4. ISBN 9780080560649.

[Stocking-3] Stocking, Emily M.; Schwarz, Jessie N.; Senn, Hans; Salzmann, Michael; Silks, Louis A. (1 January 1997). "Synthesis of L-selenocystine,L-[77Se]selenocystine and L-tellurocystine". Journal of the Chemical Society, Perkin Transactions 1 (16): 2443–2448. doi:10.1039/A600180G. ISSN 1364-5463.

[4] Ramadan, ShadiaE.; Razak, A.A.; Ragab, A.M.; El-Meleigy, M. (1 June 1989). "Incorporation of tellurium into amino acids and proteins in a tellurium-tolerant fungi". Biological Trace Element Research. 20 (3): 225–232. Bibcode:1989BTER...20..225R. doi:10.1007/BF02917437. ISSN 0163-4984. PMID 2484755. S2CID 9439946.

[5] Liu, Xiaoman; Silks, Louis A.; Liu, Cuiping; Ollivault-Shiflett, Morgane; Huang, Xin; Li, Jing; Luo, Guimin; Hou, Ya-Ming; Liu, Junqiu; Shen, Jiacong (2 March 2009). "Incorporation of Tellurocysteine into Glutathione Transferase Generates High Glutathione Peroxidase Efficiency". Angewandte Chemie International Edition. 48 (11): 2020–2023. doi:10.1002/anie.200805365. PMID 19199319.

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