Poly (ADP-ribose) polymerase (PARP) catalyzes the post-translational modification of proteins by the addition of multiple ADP-ribose moieties. PARP transfers ADP-ribose from nicotinamide dinucleotide (NAD) to glu/asp residues on the substrate protein, and also polymerizes ADP-ribose to form long/branched chain polymers. PARP inhibitors are being developed for use in a number of pathologies including cancer, diabetes, stroke and cardiovascular disease.