Inactivation of γ-aminobutyric acid aminotransferase by (S)-4-amino-4,5-dihydro-2-furancarboxylic acid does not proceed by the expected aromatization mechanism

Inactivation of pyridoxal 5′-phosphate (PLP)-dependent γ-aminobutryic acid aminotransferase by (S)-4-amino-4,5-dihydro-2-furancarboxylic acid (SADFA) gives pyridoxamine 5′-phosphate, not the expected SADFA-PLP aromatization product. Inactivation appears to proceed by a Michael addition/hydrolysis mechanism instead.