A PAD inhibitor (IC50s = 29.5 and 350 µM for PAD1 and PAD3, respectively, in vitro; irreversibly inactivates four PAD subtypes (kinact/KI = 2,800, 380, 170, and 3,000 M-1min-1); cytotoxic to HL-60, MCF-7, and HT-29 cancer cell lines (IC50s = 0.5, 0.5 and 1 μM, respectively)