We have previously shown thatMycobacterium tuberculosisFprA, an NADPH-ferredoxin reductase homologous to mammalian adrenodoxin reductase, promotes the oxidation of NADP + to its 4-oxo derivative 3-car-boxamide-4-pyridone adenine dinucleotide phosphate [Bossi RT, Aliverti A, Raimondi D, Fischer F, Zanetti G, Ferrari D, Tahallah N, Maier CS, Heck AJ, Rizzi Met al.