Chromosome 9 Open Reading Frame 95 （C9ORF95/NRK1） is a member of the uridine kinase family. NAD+ is vital for life in all organisms， both as a coenzyme for oxidoreductases and as a source of ADPribosyl groups used in countless reactions， including those which delay aging in experimental systems. Nicotinic acid and nicotinamide are defined as the vitamin precursors of NAD+. C9ORF95 catalyzes the phosphorylation of nicotinamide riboside （NR） and nicotinic acid riboside （NaR） to form nicotinamide mononucleotide （NMN） and nicotinic acid mononucleotide （NaMN）. C9ORF95 also phosphorylates the antitumor drugs tiazofurin and 3-deazaguanosine.
