Aspartate decarboxylase (PanD) (PanD)

Pyrazinamide is an oral antitubercular agent used in combination regimens to shorten and improve tuberculosis treatment. It is a prodrug that penetrates Mycobacterium tuberculosis, where it is converted to its active form, pyrazinoic acid, by the enzyme pyrazinamidase (pncA). The active metabolite binds to the bacterial aspartate decarboxylase (PanD), promoting its degradation and thus blocking the biosynthesis of coenzyme A, a molecule essential for bacterial energy metabolism and survival. Pyrazinamide is uniquely effective against slow-growing and persistent tubercle bacilli typically resistant to other drugs, especially in the acidic conditions of necrotic or inflamed tissue. Resistance most often arises due to mutations in the pncA gene. This mechanism is unusual in that the drug does not directly inhibit enzyme activity, but rather triggers protein degradation, making PanD an indirect but essential therapeutic target[1][4][5][6].

Other names

PanDAspartate 1-decarboxylasepanD gene product

Pyrazinamide is converted by bacterial pyrazinamidase (pncA) into the active metabolite, pyrazinoic acid (POA)[1][4][5]. Pyrazinoic acid binds to and destabilizes aspartate decarboxylase (PanD), triggering its degradation and blocking the synthesis of coenzyme A, which is essential for Mycobacterium tuberculosis survival[1][4]. Additional effects proposed for POA include disruption of mycobacterial membrane energetics, cytoplasmic acidification, and impaired transport functions, especially under acidic conditions where the drug is most active[2][5][6].