Nicotinamide/nicotinate mononucleotide (NMN/ NaMN)adenylyltransferase (NMNAT). NMNAT represents the primary bacterial and eukaryotic adenylyltransferases for nicotinamide-nucleotide and for the deamido form, nicotinate nucleotide. It is an indispensable enzyme in the biosynthesis of NAD(+) and NADP(+). Nicotinamide-nucleotide adenylyltransferase synthesizes NAD via the salvage pathway, while nicotinate-nucleotide adenylyltransferase synthesizes the immediate precursor of NAD via the de novo pathway. Human NMNAT displays unique dual substrate specificity toward both NMN and NaMN, and can participate in both de novo and salvage pathways of NAD synthesis. This subfamily consists strictly of eukaryotic members and includes secondary structural elements not found in all NMNATs.
Jiyao W et al.(2023). "The conserved domain database in 2023.",