(NMNAT3) Active Protein

This gene encodes a member of the nicotinamide/nicotinic acid mononucleotide adenylyltransferase family. These enzymes use ATP to catalyze the synthesis of nicotinamide adenine dinucleotide or nicotinic acid adenine dinucleotide from nicotinamide mononucleotide or nicotinic acid mononucleotide, respectively. The encoded protein is localized to mitochondria and may also play a neuroprotective role as a molecular chaperone. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Jan 2011]

NMNAT3: Catalyzes the formation of NAD(+) from nicotinamide mononucleotide (NMN) and ATP. Can also use the deamidated form; nicotinic acid mononucleotide (NaMN) as substrate with the same efficiency. Can use triazofurin monophosphate (TrMP) as substrate. Can also use GTP and ITP as nucleotide donors. Also catalyzes the reverse reaction, i.e. the pyrophosphorolytic cleavage of NAD(+). For the pyrophosphorolytic activity, can use NAD (+), NADH, NAAD, nicotinic acid adenine dinucleotide phosphate (NHD), nicotinamide guanine dinucleotide (NGD) as substrates. Fails to cleave phosphorylated dinucleotides NADP(+), NADPH and NAADP(+). Protects against axonal degeneration following injury. Belongs to the eukaryotic NMN adenylyltransferase family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Mitochondrial; Apoptosis; Transferase; EC 2.7.7.1; EC 2.7.7.18; Cofactor and Vitamin Metabolism - nicotinate and nicotinamide

Chromosomal Location of Human Ortholog: 3q23

Cellular Component: mitochondrion; cytosol

Molecular Function: nicotinamide-nucleotide adenylyltransferase activity; nicotinate-nucleotide adenylyltransferase activity; ATP binding

Biological Process: NAD biosynthetic process; vitamin metabolic process; NAD metabolic process; response to wounding; water-soluble vitamin metabolic process