Like most other amino acids, allothreonine is a water-soluble colorless solid.

Although not one of the proteinogenic amino acids, it has often been the subject for the synthesis of novel proteins using an expanded genetic code.

[1] Racemic allothreonine can be produced in the laboratory from bromomethoxybutyric acid.

Allothreonine has S, S stereochemistry at carbons 2 and 3 in the natural stereoisomer, but R, R in the very rare enantiomer.

[3] Peptides containing the allothreonine residue have also been isolated from natural source.