AmmTX3

Product Name:AmmTX3

Synonyms:Potassium channel toxin α-KTx 15.3

Purity:95%

Molar Mass:3822

Chemical Formula:C158H262N50O48S6

Storage:Store at -20 degrees Celsius

Sequence:ZIETNKKCQGGSCASVCRKVIGVAAGKCINGRCVCYP

Target:KV4 K+ channels

Application:AmmTX3 is a peptide toxin derived from the venom of the scorpion Androctonus mauretanicus. It acts as a potent and selective inhibitor of voltage-gated potassium channels, particularly Kv4.2 and Kv4.3, which are involved in the regulation of neuronal excitability and cardiac function. AmmTX3 is valuable in neurophysiology research, where it helps to study the modulation of potassium currents and their role in controlling action potential repolarization. This peptide can also be useful in investigating cardiac arrhythmias and neurological disorders associated with abnormal potassium channel activity. Its selective action makes it a key tool for exploring ion channel function in various physiological systems.

Current Research:

AmmTX3 is a peptide toxin isolated from the venom of the scorpion Androctonus mauretanicus, commonly known as the Moroccan fat-tailed scorpion. This toxin is a member of the α-KTx15 subfamily and functions as a specific blocker of A-type voltage-gated potassium (Kv4) channels.

Structural Characteristics

AmmTX3 is composed of 37 amino acid residues, cross-linked by three disulfide bridges, resulting in a molecular mass of approximately 3823.5 Da. The presence of a dyad motif, consisting of lysine at position 27 and tyrosine at position 36, is characteristic of pore-blocking potassium channel-specific toxins, suggesting that AmmTX3 acts by occluding the channel pore.

Mechanism of Action

AmmTX3 exhibits high affinity for Kv4 channels, binding with a dissociation constant (K_d) of 66 pM in rat brain synaptosomes. By blocking these channels, AmmTX3 inhibits A-type potassium currents, which play a crucial role in regulating neuronal excitability, including action potential firing frequency and spike initiation.

Biological Activity

In vitro studies have demonstrated that AmmTX3 effectively blocks A-type potassium currents in cerebellar granule cells and striatal neurons, with half-maximal inhibitory concentration (IC₅₀) values around 130 nM. This blockade can influence neuronal firing patterns, making AmmTX3 a valuable tool for studying the physiological roles of Kv4 channels in the central nervous system.

Research Applications

Due to its specificity and potency, AmmTX3 is utilized in neurophysiological research to investigate the functions of Kv4 channels in neuronal activity and their implications in neurological disorders. Its ability to modulate action potential dynamics provides insights into the mechanisms underlying synaptic transmission and plasticity.

Conclusion

AmmTX3 serves as a potent and selective inhibitor of Kv4 channels, offering significant utility in exploring the physiological and pathological roles of these channels in the nervous system. Its application in research continues to enhance our understanding of neuronal excitability and associated neurological conditions.

Reference:

Maffie, J. K., Dvoretskova, E., Bougis, P. E., Martin‐Eauclaire, M. F., & Rudy, B. (2013). Dipeptidyl‐peptidase‐like‐proteins confer high sensitivity to the scorpion toxin AmmTX3 to Kv4‐mediated A‐type K+ channels. The Journal of physiology, 591(10), 2419-2427.