2.7.1.173	evolution	the enzyme is structurally similar to Rossmann fold metabolite kinases	718250	
2.7.1.173	malfunction	in NRK1-silenced cells, both nicotinamide riboside- and NMN-mediated rescue from FK866-induced NAD+ depletion and cell death are potently and significantly reduced, overview	739212	
2.7.1.173	metabolism	distinct metabolic routes, starting from various precursors, are known to support NAD+ biosynthesis with tissue/cell-specific efficiencies, probably reflecting differential expression of the corresponding rate-limiting enzymes, i.e. nicotinamide phosphoribosyltransferase, quinolinate phosphoribosyltransferase, nicotinate phosphoribosyltransferase and nicotinamide riboside kinase	738213	
2.7.1.173	metabolism	in addition to the seven-component pyridine nucleotide cycle, an eight-component cycle involving nicotinate riboside kinase operates in plants. NaR kinase does not make a significant contribution to salvage for pyridine nucleotide synthesis	718225	
2.7.1.173	metabolism	nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiated by splitting the nucleoside into a nicotinamide base followed by nicotinamide salvage. Yeast nicotinic acid riboside utilization largely depends on uridine hydrolase and nicotinamide riboside kinase, and nicotinic acid riboside bioavailability is increased by ester modification	-, 698901	
2.7.1.173	metabolism	the enzyme is involved in the eukaryotic nicotinamide riboside kinase, Nrk, pathway, which is induced in response to nerve damage and promotes replicative life span in yeast, converts nicotinamide riboside to NAD+ by phosphorylation and adenylylation, overview. Nicotinic acid riboside is utilized in vivo by Urh1, Pnp1, and Preiss-Handler salvage	718250	
2.7.1.173	metabolism	the enzyme is involved in the NAD+ biosynthesis pathway. In the initial step of the pathway, NRK activity catalyses the phosphorylation of nicotinamide riboside (NR) to nicotinamide mononucleotide (NMN), see for EC 2.7.1.22. Importance of different salvage pathways involved in metabolising the vitamin B3 class of NAD+ precursor molecules, with a particular focus on the nicotinamide riboside kinase pathway at both a tissue-specific and systemic level, regulation of the NRK enzymes, overview. Alternatively, NRK activity can phosphorylate nicotinic acid riboside (NaR) to nicotinic acid mononucleotide (NaMN)	761705	
2.7.1.173	additional information	comparison to the Nrk-independent utilization pathway of nicotinamide riboside in yeast, overview	-, 698901	
2.7.1.173	additional information	proposed NRK expression in disease and potential therapeutic interventions	761705	
2.7.1.173	physiological function	nicotinamide riboside is a relevant NAD+ precursor	738213	
2.7.1.173	physiological function	nicotinamide riboside kinase has an important role in the biosynthesis of NAD+ as well as the activation of tiazofurin and other nicotinamide riboside analogues for anticancer therapy	682879	
2.7.1.173	physiological function	nicotinamide riboside kinase increases the NAD+ levels via convertion of the substrate nicotinamide riboside and thereby extending replicative lifespan and increases Sir2-dependent gene silencing	-, 698901	
2.7.1.173	physiological function	NRK2 appears to play a redundant role in NAD+ biosynthesis along with NRK1, at least in unchallenged models, its highly regulated expression particularly in times of stress suggest it may have role beyond NAD+ metabolism	761705