PncA

PncA is a bacterial gene encoding a nicotinamidase that doubles as a pyrazinamidase in Mycobacterium species.¹ Nicotinamidase converts nicotinamide to nicotinic acid where as pyrazinamidase converts the drug pyrazinamide to its active form pyrazinoic acid.²

Missense mutations in this gene in Mycobacterium is strongly correlated with resistance to pyrazinamide, likely due to a loss of the ability to produce pyrazinoic acid.³ Mutagenesis data indicates that many loss-of-function mutations differentially affect the enzyme's ability to convert nicotinamide and pyrazinamide.⁴

The H57D resistance mutation is "typical of" M. bovis.³

The symbol PncA is also used for the orthologous nicotinamidase in other bacterial species, including E. coli.⁵