APETx2

APETx2 is a toxin that was originally isolated from Anthopleura elegantissima (Sea anemone). APETx2 selectively blocks the H(+)-gated sodium channel ASIC3 (ACCN3). The blockage is rapid and reversible. This toxin does not block isoform ASIC1a and isoform ASIC1b of ASIC1 (ACCN2), nor ASIC2 (ACCN1). It also inhibits the heteromeric ASIC2b-ASIC3 channel. It has less affinity for ASIC1b-ASIC3, ASIC1a-ASIC3, and no effect on the ASIC2a-ASIC3 channels. IC50 is 63 nM on ASIC3 channel. IC50 is 117 nM on ASIC2b-ASIC3 heteromeric channel. IC50 is 0.9 μM on ASIC1b-ASIC3 heteromeric channel. IC50 is 2 μM on ASIC1a-ASIC3 heteromeric channel.