NAPRT

Nicotinic acid (NA; niacin) is converted by nicotinic acid phosphoribosyltransferase (NAPRT; EC 2.4.2.11) to NA mononucleotide (NaMN), which is then converted to NA adenine dinucleotide (NaAD), and finally to nicotinamide adenine dinucleotide (NAD), which serves as a coenzyme in cellular redox reactions and is an essential component of a variety of processes in cellular metabolism including response to stress (Hara et al., 2007).[supplied by OMIM, Mar 2008]

Nicotinate Phosphoribosyltransferase

Catalyzes the first step in the biosynthesis of NAD from nicotinic acid, the ATP-dependent synthesis of beta-nicotinate D-ribonucleotide from nicotinate and 5-phospho-D-ribose 1-phosphate (PubMed:17604275, PubMed:21742010, PubMed:26042198).

Helps prevent cellular oxidative stress via its role in NAD biosynthesis (PubMed:17604275).

NAD salvage Source: GO_Central
Response to oxidative stress Source: UniProtKB

Cytosol

Transiently phosphorylated on a His residue during the reaction cycle. Phosphorylation strongly increases the affinity for substrates and increases the rate of nicotinate D-ribonucleotide production. Dephosphorylation regenerates the low-affinity form of the enzyme, leading to product release.