Nicotinamide mononucleotide adenylyltransferase 3 (NMNAT3) is an enzyme that in humans is encoded by the NMNAT3 gene. [1]
NMNAT3 is the third of three protein isoforms of nicotinamide-nucleotide adenylyltransferase (NMNAT) found in humans. [2] As with the other NMNATs, NMNAT3 is an enzyme that catalyzes nicotinamide adenine dinucleotide (NAD) synthesis. [2] NMNAT3 levels are highest in liver, heart, skeletal muscle, and erythrocytes. [2]
NMNAT3 is localized in mitochondria or cytoplasm, depending upon the cell type. [3] [4] [5] Knockdown of NMNAT3 gene expression in cell culture strongly reduces mitochondrial function. [4] NMNAT3 is essential for maintaining NAD in red blood cells. [4]
The catechin epigallocatechin gallate found in tea can activate NMNAT3 by more than 40%. [5]
As of 2024, mutations in the NMNAT3 gene have not been associated with any known human disease, [2] but NMNAT3 deficiency causes hemolytic anemia in mice. [6]