Utilization of 2'-deoxynad for ADP-ribose transfer reactions

2'-deoxyNAD was examined as a substrate for both mono(ADP-ribosyl)ation and poly(ADP-ribosyl)ation reactions. 2'-deoxyNAD is a substrate for the diphtheria toxin-catalyzed mono(ADP-ribosyl)ation of elongation factor-2, inactivating its function to enhance protein synthesis. On the other hand, 2'-deoxyNAD is a poor substrate for poly(ADP-ribose) polymerase. 2'-deoxyNAD was not synthesized intracellularly from deoxyATP, even when deoxyATP content was markedly increased by incubation of cells with deoxyadenosine and an adenosine deaminase inhibitor. 2'-deoxyNAD, because of its specificity, could be a quite useful reagent for the investigation of cellular mono(ADP-ribosyl)ation reactions.