Catalyzes the deamidation of nicotinamide (NAM) into nicotinate (PubMed:18201201). Likely functions in the cyclical salvage pathway for production of NAD from nicotinamide (By similarity). Is involved in the activation of the first-line antituberculous drug pyrazinamide (PZA) by converting it into the active form, pyrazinoic acid. H2O + nicotinamide = NH4(+) + nicotinate H2O + pyrazinamide = NH4(+) + pyrazine-2-carboxylate PncA contains Mn(2+) and Fe(2+) in a molecular ratio of 1:1. PncA has only one metal center. It is believed that PncA binds iron in the natural state, although both metals can support enzymatic activity. Is inhibited by Cu(2+), Zn(2+) and Fe(3+). Optimum pH is 7.0 for the hydrolysis of nicotinamide. The enzyme activity decreases rapidly below pH 6.0 or above pH 8.0. Optimum temperature is 40 degrees Celsius for the hydrolysis of nicotinamide. Below 25 or above 70 degrees Celsius, the enzyme loses its activity rapidly. Cofactor biosynthesis; nicotinate biosynthesis; nicotinate from nicotinamide: step 1/1. Monomer. Most pyrazinamide-resistant clinical M.tuberculosis isolates contain mutations in the pncA gene, causing lack or reduction of PZAase activity. Belongs to the isochorismatase family.