Other · Scorpion α-KTx voltage-gated potassium-channel blocker
Agitoxin-2
Also known as AgTx2; α-KTx 3.2
A 38-residue scorpion peptide used to map the extracellular pore and toxin-binding surfaces of Shaker-family potassium channels.
- Length
- 38 amino acids
- Half-life
- Not well characterised
- Mechanism
- Agitoxin-2 occludes the extracellular pore of susceptible Shaker-family and mammalian Kv1 potassium channels. A conserved lysine on its binding surface contributes to pore blockade, while surrounding residues determine affinity for particular channel vestibules.
- Studied in
- Recombinant Shaker and Kv1 channel systems use agitoxin-2 in electrophysiology, mutagenesis and structural studies of toxin–pore recognition.
About Agitoxin-2
Agitoxin-2 is one of the related agitoxin peptides isolated from venom historically attributed to Leiurus quinquestriatus hebraeus, now commonly recognised as Leiurus hebraeus. Characterised in the 1990s, it contains 38 amino acids and three disulphide bonds. Its cysteine-stabilised α/β framework supports a compact surface for potassium-channel recognition. The numbering distinguishes it from other agitoxins with related but non-identical sequences, so an unspecified agitoxin preparation should not be assumed to contain this particular molecular species.
A major research role for agitoxin-2 is probing the outer pore of Shaker-family potassium channels through toxin and channel mutagenesis. Interactions involving its conserved lysine and nearby surface residues have helped define how peptide blockers recognise the selectivity-filter region and surrounding vestibule. Mammalian Kv1.1, Kv1.3 and Kv1.6 are among reported susceptible channels. Because affinity depends on the channel sequence and experimental conditions, quantitative comparisons require matched expression systems and carefully controlled electrophysiological protocols.
Laboratory notes
- Confirm the agitoxin isoform and correctly folded, three-disulphide molecular form before comparing results across suppliers.
- Control extracellular potassium and ionic strength, which can influence toxin–channel interactions and apparent blocking affinity.
- For research use only. Include channel-expression controls and follow institutional procedures for handling potent peptide toxins.
Storage and reconstitution basics: storage guide.
Questions about Agitoxin-2
What distinguishes agitoxin-2 from agitoxin-1 or agitoxin-3?
They are related venom peptides with distinct amino-acid sequences. Their binding properties should be assessed separately rather than treated as interchangeable.
Why is agitoxin-2 useful for channel mutagenesis studies?
Changes in toxin affinity after defined channel mutations can help identify residues involved in extracellular pore recognition, provided channel function remains intact.
Is agitoxin-2 a channel activator?
No. It is principally used as an extracellular pore blocker that suppresses potassium conduction through susceptible channels.
Is Agitoxin-2 for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.