Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Kensei KobayashiEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1590-4


Threonine is one of the protein amino acids whose chemical formula is HO2CCH(NH2)CH(OH)CH3. Its three-letter symbol is Thr, and its one-letter symbol is T. As in the case of serine, it has a hydroxyl (−OH) group in its side chain, and it is classified as a polar amino acid. Its molecular weight is 119.12, and its isoelectric point is 6.16. Threonine has two asymmetric carbons (α-carbon and β-carbon) as does isoleucine. Thus, threonine has four stereoisomers: l-threonine, d-threonine, l-allo-threonine, and d-allo-threonine. Only l-threonine is used in biosynthesis of proteins, and it is widely distributed in the biosphere.

See Also


Molecular Weight Bioorganic Chemistry Isoelectric Point Chemical Formula Protein Amino Acid 
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© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Yokohama National UniversityYokohamaJapan