β-decarboxylation of l-aspartic acid: A metal chelate-catalyzed reaction

✍ Scribed by N.Y. Sakkab; A.E. Martell

• Publisher: Elsevier Science
• Year: 1975
• Weight: 288 KB
• Volume: 5
• Category: Article
• ISSN: 0006-3061
• DOI: 10.1016/s0006-3061(00)80222-7

✦ Synopsis

&decarboxylation of L-aspartic acid was observed in the system, pyridoxal: L-aspartic acid:aluminum(III), 1 I 100. -1 when heated at 80" for three hours. This reaction was followed by electronic spectroscopy and showed quantitative conversion of pyridoxal to pyridoxamine indicating decarboxylation of the ketimine. a-Methyl-l-aspartic acid was not decarboxylated indicating the presence of the a-proton and prior transamination as requirements for decarboxylation. When pyridoxamine and oxalo-Zpropionic acid were reacted at pD 4.60, product analysis by nmr showed the presence of pyridoxamine and o-ketobutyric acid, indica;ing hydrolysis of the decarboxylated ketimine. Decarboxylation was fast compared to spontaneous decarboxylation. A mechanism is proposed for non-enzymatic decarboxylation and the previously suggested mechanism for the inactivation of the enzyme aspartate p-decarboxylase is discussed_