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.1 Without photoactivation, it is a weak inhibitor of PAD2 (IC50 = >100 μM) and is less potent than BB-Cl-amidine in inhibiting citrulline production in vitro (kinact/KIs = 2,300, 600, 1,000, and 10,510 M-1min-1 for PAD1-4, respectively) and does not inhibit histone H3 citrullination in HEK293T cells overexpressing PAD2 when used at concentrations up to 100 μM. 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 with an IC50 value of 9.1 μM.
References
1. Mondal, S., Parelkar, S.S., Nagar, M., et al. Photochemical control of protein arginine deiminase (PAD) activity. ACS Chem. Biol. 13(4), 1057-1065 (2018).