famidine

F-amidine is a bioavailable irreversible PAD4 inactivator.

F-amidine is a selective inhibitor of protein arginine deiminases (PADs), specifically targeting PAD1 and PAD4 with in vitro IC50 values of 29.5, 350, and 21.6 µM for PAD1, PAD3, and PAD4, respectively. It irreversibly inactivates all four PAD subtypes by covalently modifying an active site cysteine crucial for enzymatic activity, with kinact/KI values of 2,800, 380, 170, and 3,000 M^-1min^-1. Additionally, F-amidine demonstrates cytotoxicity against HL-60, MCF-7, and HT-29 cancer cell lines, with IC50s of 0.5, 0.5, and 1 μM, respectively.