Stereoisomerism
| |
| -Threonine (2S,3R) and -Threonine (2R,3S) |
| |
| -allo-Threonine (2S,3S) and -allo-Threonine (2R,3R) |
Threonine is one of two amino acids out of the twenty with two chiral centers. Threonine can exist in four possible stereoisomers with the following configurations: (2S,3R), (2R,3S), (2S,3S) and (2R,3R). However, the name -threonine is used for one single diastereomer, (2S,3R)-2-amino-3-hydroxybutanoic acid. The second stereoisomer (2S,3S), which is rarely present in nature, is called -allo-threonine. The two stereoisomers (2R,3S)- and (2R,3R)-2-amino-3-hydroxybutanoic acid are only of minor importance.
Read more about this topic: Threonine