Nicotinic acid riboside is a NAD+ precursor in human cells. Nicotinic acid riboside is an authentic intermediate of human NAD+ metabolism[1][2].
Nicotinic acid riboside (HepG2 cells; 0.01 nM~0.1 mM) helps FK866-treated cells to maintain viability at low micromolar concentrations[1]..Nicotinic acid riboside formation and release are caused by overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells. CN-II and CN-III generate Nicotinic acid riboside in vitro by dephosphorylation of nicotinic acid mononucleotide (NAMN)[1].
[1]. Sasaki Y, et al. Nicotinic acid mononucleotide is an allosteric SARM1 inhibitor promoting axonal protection. Exp Neurol. 2021;345:113842.
[2]. Bogan KL, et al. Identification of Isn1 and Sdt1 as glucose- and vitamin-regulated nicotinamide mononucleotide and nicotinic acid mononucleotide [corrected] 5’-nucleotidases responsible for production of nicotinamide riboside and nicotinic acid riboside [published correction appears in J Biol Chem. 2010 Jan 29;285(5):3524]. J Biol Chem. 2009;284(50):34861-34869.