Inactivation of GABA transaminase by 4-acryloylphenol

Previous study showed that 4-hydroxybenzaldehyde is a competitive inhibitor of GABA transaminase. As a result, 4-acryloylphenol was synthesized as a 4-hydroxybenzaldehyde analogue, and shown to inactivate potently the enzyme in a time-dependent manner. The inactivation was protected by α-ketoglutarate, indicating that it occurs at the active site of the enzyme. β-Mercaptoethanol also prevented the enzyme from inactivation. The possible mechanism involving a Michael addition was proposed to rationalize the inactivation.