- Er, S.Y. et al. (2017) Neuropharmacology 127, 185.
- Alomone Labs Hm3a Toxin inhibits ASIC1a channels expressed in Xenopus oocytes.A. Representative time course of Hm3a Toxin (#STH-250) inhibition of ASIC1a currents. Membrane potential was held at -80 mV, current was elicited every 50 sec by a transient application of pH 5.5 and inhibited by a 4 min application of 1 nM Hm3a Toxin, as indicated. B. Superimposed traces of ASIC1a currents upon application of control and of 1 nM Hm3a Toxin (taken from the experiment in A).
Hm3a is a 37-amino acid peptide toxin originally isolated from the venom of Togo starburst tarantula (Heteroscodra maculata) and acts as a potent ASIC1a channel blocker with an IC50 value of 1-2 nM and ASIC1b channel activator with an EC50 value of 46.5 nM1. Studies reveal that Glu177 and Arg175 in the palm region opposite α-helix 5 play an important role in the interaction between Hm3a and ASIC1 and contribute to the subtype-dependent effects of the peptide. Hm3a is a useful tool for studying ASICs1.
Acid-sensing ion channels (ASICs) are voltage-independent proton-gated amiloride sensitive sodium channels, belonging to the DEG/ENaC gene family, activated by a drop in extracellular pH. ASIC1a is a promising therapeutic target1,2.
Hm3a Toxin (#STH-250) is a highly pure, synthetic, and biologically active peptide toxin.