Azetidine-2-Carboxylic Acid (ACA)

Azetidine-2-carboxylic acid is a plant non-protein amino acid homologue of proline with the molecular formula C4H7NO2. Aze is a heterocyclic, 4 membered ring with nitrogen as its heteroatom (an azetidine), and a carboxylic acid group substituted on one of the ring carbon atoms. Aze has the ability to act as an analog of proline and can be incorporated into proteins in place of proline. Optically inactive Aze was obtained in small yield from γ-aminobutyric acid by α-bromination, followed by removal of hydrogen bromide from the intermediate γ-amino-α-butyric acid and ring closure by treatment with a barium hydroxide solution. It has been shown that when Azetidine-2-carboxylic acid is misincorporated into proteins in place of proline, Aze deters the growth of competing vegetation and poisons predators. Misincorporation of Aze into human proteins can alter collagen, keratin, hemoglobin, and protein folding.