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κ-theraphotoxin-Ps1aκ-TRTX-Ps1a, PaTX1
A Potent Blocker of KV4.2 and KV4.3 Channels
Cat #: STP-700
Alternative Name κ-theraphotoxin-Ps1aκ-TRTX-Ps1a, PaTX1
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Synthetic peptide
    MW: 3549 Da.
    Purity: >99% (HPLC)
    Effective concentration 10-100 nM.
    Modifications Disulfide bonds between Cys2-Cys16, Cys9-Cys21, and Cys15-Cys25. Ile29 – C-terminal amidation.
    Molecular formula C156H240N44O37S7.
    CAS No.: 221872-97-5.
    Activity Phrixotoxin-1 specifically and reversibly blocks KV4.2 and KV4.3 channels1.
    1. Chagot, B. et al. (2004) Protein Sci. 13, 1197.
    Shipping and storage Shipped at room temperature. Product as supplied can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Solubility Any aqueous buffer. Centrifuge all product preparations before use (10,000 x g 5 min).
    Storage of solutions Up to two weeks at 4°C or three months at -20°C.
    Our bioassay
    • Alomone Labs Phrixotoxin-1 inhibits KV4.2 channels expressed in Xenopus oocytes.
      Alomone Labs Phrixotoxin-1 inhibits KV4.2 channels expressed in Xenopus oocytes.
      A. Time course of Phrixotoxin-1 (#STP-700) action on KV4.2 current amplitude recorded at 10 mV. Current amplitudes were plotted as a function of time. Membrane potential was held at -100 mV and oocytes were stimulated by a 100 ms voltage ramp to +20 mV. 50 nM Phrixotoxin-1 was perfused as indicated by the bar (green) for 220 sec. B. Superimposed examples of KV4.2 channel current in the absence (control) and presence (green) of 50 nM Phrixotoxin-1 (taken from the experiment in A).
    References - Scientific background
    1. Diochot, S. et al. (1999) Br. J. Pharmacol. 126, 251.
    2. Chagot, B. et al. (2004) Protein Sci. 13, 1197.
    Scientific background

    Phrixotoxin-1 (PaTx1) is a 29 amino acid peptidyl toxin isolated from the venom of the theraphosid Phrixotrichus auratus, which potently blocks A-type K+ currents.

    PaTx1 specifically blocks KV4.3 and KV4.2 currents with a 5 nM < IC50 < 70 nM, by modifying the gating properties of these channels.1

    As with other spider toxins, PaTx1 presents an active molecular surface, including a hydrophobic patch surrounded by charged residues, which are important for their binding on KV channels. Electrophysiological studies show that the PaTx1 blocks KV4 channels via a mechanism similar to that of hanatoxins on KV2 channels, as they bind and stabilize the preferentially closed state of the channel, in a voltage-dependent manner.2

    PaTx1 is a crucial tool for understanding the contribution of KV4.3 and KV4.2 in cardiac electrogenesis. Treatment of mice with PaTx1 results in numerous transient cardiac adverse reactions including the occurrence of premature ventricular beats, ventricular tachycardia, different degrees of atrioventricular (AV) blockage and prolongation of the QT interval.1

    Target KV4.2, KV4.3 channels
    Net Peptide Content: 100%
    Image & Title Phrixotoxin-1 Alomone Labs Phrixotoxin-1 blocks KV4 currents in mouse preoptic GABAergic neurons.K+ currents were elicited by a depolarizing step to 220 mV in control (left), during Phrixotoxin-1 (#STP-700), (600 nM) incubation (middle) and the Phrixotoxin-1-sensitive component obtained by subtraction (right). Phrixotoxin-1 blocked 76 ± 11% (n = 5, P,0.01 paired t-test relative to control amplitudes) of IA currents.Adapted from Sethi, J. et al. (2011) PLoS ONE 6, e29134. with permission of PLoS.
    Last update: 23/08/2020

    Phrixotoxin-1 (#STP-700) is a highly pure, synthetic, and biologically active peptide toxin.

    For research purposes only, not for human use



    Scientific Background


    Product citations
    1. Salari, A. et al. (2016) Sci. Rep. 6, 1.
    2. Wright, T. et al. (2016) Sci. Rep. 6, 28584.
    3. Sethi, J. et al. (2011) PLoS ONE 6, e29134.
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