Nicotinamide Nucleotide Adenylyltransferase 3 (NMNAT3)

NMNAT (EC 2.7.7.1) is a central enzyme in NAD biosynthesis, catalyzing the condensation of nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN) with the AMP moiety of ATP to form NAD or NaAD.The deduced 252-amino acid protein contains the signature adenylyltransferase motif.

NMNAT3 shares 50% amino acid identity with NMNAT1 and 82% identity with mouse Nmnat3. Northern blot analysis detected a 1.1-kb transcript expressed at high levels in lung and spleen and at lower levels in placenta and kidney. Little to no expression was detected in any other normal tissue examined or in any cancer cell lines examined. Fluorescence-tagged NMNAT3 was expressed in the cytosol of transfected HEK293 and HeLa cells. NMNAT3 was also detected within mitochondria.