Photoswitchable PAD inhibitor is a photoactivated protein arginine deiminase (PAD) inhibitor and a derivative of BB-Cl-amidine that contains an azobenzene photoswitch allowing optical control of PAD activity. Without photoactivation, it is a weak inhibitor of PAD2 and is less potent than BB-Cl-amidine in inhibiting citrulline production in vitro. It does not inhibit histone H3 citrullination in HEK293T cells overexpressing PAD2. However, it can rapidly be photoactivated with UV-A radiation to the more active cis-isomer, which is an irreversible, competitive inhibitor of histone H3 citrullination.
