AbstractThe synthesis of [1‐15N]nicotinamide adenine dinucleotide is described. Chemical shift data from15N NMR studies are presented for the pyridine ring nitrogen of labeled NAD and related compounds. The results indicate a15N label in the N‐1 position to be highly sensitive to the redox‐state of the pyridine moiety, with an upfield shift of over 100 ppm observed upon reduction of NAD+to NADH. The feasibility of conducting15N NMR studies of pyridine nucleotide binding to dehydrogenases is disc