2-(2-aminobut-3-enyl)propanedioic acid is a naturally occurring non-protein amino acid, also known as l-allyl glycine. This acid is involved in various metabolic processes and is found in many plants, animals, and microorganisms. In 1931, Heilbron and Hodge first identified the L-allylglycine component in plant extracts. At the time, researchers noted that L-allyl glycine is a very potent inhibitor of alanine aminotransferase, and later found that it also inhibits cystathionine γ-synthetase.