title: Sequence of reactions which follows enzymatic oxidation of propargylglycine.
abstract: The nonenzymatic reactions which follow enzymatic oxidation of the gamma-delta acetylenic amino acid propargylglycine (2-amino-4-pentynoate) have been studied. The product which accumulates in solution has been identified as 2-amino-4-hydroxy-2,4-pentadienoate gamma-lactone, formed by intramolecular attack of the carboxylate anion on the electrophilic fourth carbon of 2-iminium-3,4-pentadienoate. This previously unknown substance was characterized by its reactions in acid and base and by its nuclear magnetic resonance spectrum. The lactone is preceded in the pathway by 2-amino-2-penten-4-ynoate, a transient electron-rich species which binds tightly to D-amino-acid oxidase and induces a charge-transfer complex with the electron-deficient bound flavin coenzyme. The aminediene lactone is converted by base treatment to 2-amino-4-keto-2-pentenoate, which is also a strong inhibitor of D-amino-acid oxidase and induces a charge-transfer complex.
mesh_terms: D000480:Alkynes; D002374:Catalase; D003605:D-Amino-Acid Oxidase; D005998:Glycine / Q000031:analogs & derivatives*; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D000637:Transaminases
chemical_list: D000480:Alkynes; C009055:propargylglycine; D002374:Catalase; D003605:D-Amino-Acid Oxidase; D000637:Transaminases; D005998:Glycine