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 . Also catalyzes the reverse reaction, i.e. the pyrophosphorolytic cleavage of NAD(+) . For the pyrophosphorolytic activity, prefers NAD(+) and NaAD as substrates and degrades NADH, nicotinic acid adenine dinucleotide phosphate (NHD) and nicotinamide guanine dinucleotide (NGD) less effectively . Involved in the synthesis of ATP in the nucleus, together with PARP1, PARG and NUDT5 . Nuclear ATP generation is required for extensive chromatin remodeling events that are energy-consuming . Also acts as a cofactor for glutamate and aspartate ADP-ribosylation by directing PARP1 catalytic activity to glutamate and aspartate residues on histones (By similarity). Fails to cleave phosphorylated dinucleotides NADP(+), NADPH and NaADP(+) . Protects against axonal degeneration following mechanical or toxic insults (By similarity).
Subcellular locations: Nucleus
Widely expressed with highest levels in skeletal muscle, heart and kidney. Also expressed in the liver pancreas and placenta. Widely expressed throughout the brain.