PAP-1 is an inhibitor of Kv1.3 voltage-gated potassium channels (EC50 = 2 nM at -80 mV in cells overexpressing the human channel).1 It is selective for Kv1.3 over a panel of 22 ion channels, including potassium, sodium, calcium, and chloride channels (EC50s = 45-15,000 nM for all). PAP-1 inhibits anti-CD3 antibody-induced proliferation of isolated human CCR7- effector memory T cells. In vivo, PAP-1 (3 mg/kg) inhibits ovalbumin-induced delayed-type hypersensitivity in rats.
1.Schmitz, A., Sankaranarayanan, A., Azam, P., et al.Design of PAP-1, a selective small molecule Kv1.3 blocker, for the suppression of effector memory T cells in autoimmune diseasesMol. Pharmacol.68(5)1254-1270(2005)