Inhibitor of PARP-3 (IC50 = 0.89 μM). Displays selectivity for PARP-3 over PARP-1, PARP-2 and other ARDT enzymes (IC50 values are 6.3, 10.8 and >30 μM respectively). Enhances CRISPR-Cas9-mediated HER2 mutation frequency, resulting in increased reduction in proliferation of HER2-positive breast cancer cells. Cell permeable. Purity 98%. MW (observed): 321.37