3-Acetylpyridine NAD (APAD) is an analog of NAD+ (free acid) , a signaling molecule and cofactor or substrate for many enzymes. APAD has been used to study the mechanisms of oxidative phosphorylation. It can be reduced by transdehydrogenase from NADH (sodium salt) . It can be reduced more efficiently and is more stable than NAD+; thus, it is useful as a substitute.
References:
[1]. Houtkooper, R.H., Cantó, C., Wanders, R.J., et al. The secret life of NAD+: An old metabolite controlling new metabolic signaling pathways Endocr. Rev. 31(2), 194-223 (2010).
[2]. Ciaccio, E.I. The inhibition of lactate dehydrogenase by 3-acetylpyridine adenine dinucleotide and bisulfite J. Biol. Chem. 241(7), 1581-1586 (1966).
[3]. Birrell, J.A., and Hirst, J. Investigation of NADH binding, hydride transfer, and NAD(+) dissociation during NADH oxidation by mitochondrial complex I using modified nicotinamide nucleotides Biochemistry 52(23), 4048-4055 (2013).
[4]. Stilwell, S.N., Bizouam, T., and Jackson, J.B. The reduction of acetylpyridine adenine dinucleotide by NADH: is it a significant reaction of proton-translocating transhydrogenase, or an artefact? Biochim Biophys. Acta. 1320(1), 83-94 (1997).
[5]. Lee, H.J., Lee, S.H., Park, C.B., et al. Coenzyme analogs: Excellent substitutes (not poor imitations) for electrochemical regeneration Chem. Commun. (Camb.) 47(46), 12538-12540 (2011).