Nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) is an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

that in humans is encoded by the ''NMNAT2''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

. This gene product belongs to the nicotinamide-nucleotide adenylyltransferase (NMNAT) enzyme family, members of which catalyze an essential step in the

nicotinamide adenine dinucleotide Nicotinamide adenine dinucleotide (NAD) is a Cofactor (biochemistry), coenzyme central to metabolism. Found in all living cell (biology), cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphat ...

(NAD+ (NADP)) biosynthetic pathway. NMNAT2 is cytoplasmic (associated with the

Golgi apparatus The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic Cell (biology), cells. Part of the endomembrane system in the cytoplasm, it protein targeting, packages proteins ...

), and is predominantly expressed in the brain. Two transcript variants encoding different isoforms have been found for this gene. Loss of NMNAT2 initiates

Wallerian degeneration Wallerian degeneration is an active process of degeneration that results when a nerve fiber is cut or crushed and the part of the axon distal to the injury (which in most cases is farther from the neuron's cell body) degenerates. A related process ...

. By contrast, NMNAT2 enhancement opposes the actions of

SARM1 Sterile alpha and TIR motif containing 1 Is an enzyme that in humans is encoded by the ''SARM1'' gene. It is the most Conserved sequence, evolutionarily conserved member of the Toll-Interleukin receptor, Toll/Interleukin receptor-1 (TIR) family. ...

which would lead to axon degeneration, but this effect is not due to preventing SARM1 depletion of NAD+. Mice lacking NMNAT2 die before birth, but are completely rescued by SARM1 deletion. Activation of NMNAT2 by Sirtuin 3 (SIRT3) may be a means of inhibiting axon degeneration and dysfunction. The

catechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tannic ...

epigallocatechin gallate Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin. EGCG – the most abundant catechin in tea – is a polyphenol under basic research for it ...

(EGCG) found in

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and nor ...

can activate NMNAT2 by more than 100%.

References

Further reading