nicotinamide mononucleotide adenylyltransferase 1; NMN adenylyltransferase 1; nicotinate-nucleotide adenylyltransferase 1; NaMN adenylyltransferase 1 (NMNAT1, NMNAT)

Function

• NAD biosynthesis
  • catalyzes formation of NAD+ from nicotinamide mononucleotide (NMN) & ATP
  • can also use deamidated form nicotinic acid mononucleotide as substrate with the same efficiency
  • also catalyzes the reverse reaction, i.e. pyrophosphorolytic cleavage of NAD+
  • for the pyrophosphorolytic activity, prefers NAD+
  • degrades NADH, nicotinic acid, adenine dinucleotide phosphate & nicotinamide guanine dinucleotide less effectively
  • does not cleave phosphorylated dinucleotides NADP+, NADPH & NAADP(+)
• protects against axonal degeneration following mechanical or toxic insults
• interacts with ADPRT/PARP1
• phosphorylated

ATP + nicotinamide ribonucleotide  <-->  diphosphate + NAD+

Cofactor:

• divalent metal cations
• Mg+2 confers the highest activity

Kinetic parameters:

• KM=34 uM for NMN
• KM=40 uM for ATP
• KM=937 uM for PPi
• KM=59 uM for NAD+
• Vmax=25 umol/min/mg enzyme for NAD synthesis
• Vmax=60.5 umol/min/ug enzyme for NAD+ cleavage
• Vmax=8.5 umol/min/ug enzyme for NADH cleavage

Inhibition:

• strongly inhibited by galotannin
• inhibited by Nap4AD

Structure

• homohexamer
• belongs to the eukaryotic NMN adenylyltransferase family

Compartment

nucleus

Expression

• widely expressed
• highest levels in skeletal muscle, heart, liver, kidney
• widely expressed throughout brain

More general terms

• nicotinamide mononucleotide adenylyltransferase
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=64802
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:64802
• OMIM: https://mirror.omim.org/entry/608700
• UniProt: http://www.uniprot.org/uniprot/Q9HAN9.html