Dehydroalanine is an organic compound with the formula . It does not exist in its free form, but it occurs naturally as a residue found in peptides of microbial origin. Unlike most amino acid residues, it has an unsaturated backbone.
Structure and reactivity
Like most primary enamines, dehydroalanine is unstable. It would hydrolyze to pyruvate: Alkaline degradation of cystine-containing peptides and proteins was shown to give derivatives containing lanthionine and lysinoalanine. N-acetyldehydroglycine was also shown to add amines.
The dehydroalanine residue was first detected in nisin, a cyclic peptide with antimicrobial activity.
Many dehydroalanine-containing peptides are toxic.
Chemical synthesis
N-Acyl dehydroalanine derivatives have been synthesized by dehydration of serines using a tert-butoxycarbonate leaving group, or by conversion of Cysteine derivatives using various reagents for the elimination of the Thiol-group. Various protected dehydroamino acids can be produced by electrochemical oxidation of the respective amino acid derivative in methanol.
Dehydroalanine derivatives have proven to be useful in late-stage peptide modification, enabling straightforward synthesis of functionally diverse peptides or proteins.