Fig. 2. Biochemical and cellular assessment of DB008 selectivity across the PARP family. (A) DB008 potency against the PARP family determined using our PASTA assay (trans-modification) unless otherwise indicated: *auto-modification assay format using native NAD⁺ (100 μM for PARP3, PARP4, and PARP7; 400 μM for PARP16). N.D. = not determined. Individual dose–response curves can be found in Fig. S5.† (B) Cellular inhibition of PARP1 was determined by treating HEK 293T cells with a dose response of PARP inhibitors (30 min) followed by PARG inhibitor (15 min) to amplify the PARylation signal. Western blotting for PARylation was done using a mono/poly ADPr antibody from cell signaling technology. (C) Quantification of inhibition from (B); n = 2 biological replicates. (D) DB008 is not a covalent inhibitor of PARP1/2 in cells. Cellular PARP1/2 inhibition assay performed as in (B), except a washout condition before PARG inhibitor treatment was included; n = 2 biological replicates.