ProTx-II

β/ω-Theraphotoxin-Tp2a, Protoxin-2, PT-II, ProTx2, Protoxin2, ProTx II
A Blocker of NaV1.7 and NaV1.5 Channels and Some T-Type Ca2+ Channels
Cat #: STP-100
Alternative Name β/ω-Theraphotoxin-Tp2a, Protoxin-2, PT-II, ProTx2, Protoxin2, ProTx II
  • Lyophilized Powder
  • Bioassay Tested
  • Origin Thrixopelma pruriens (Peruvian green velvet tarantula).
    Source Synthetic peptide
    MW: 3826.6 Da.
    Purity: >98% (HPLC)
    Effective concentration 10-500 nM.
    Sequence YCQKWMWTCDSERKCCEGMVCRLWCKKKLW.
    Modifications Disulfide bonds between Cys2-Cys16, Cys9-Cys21, and Cys15-Cys25.
    Molecular formula C168H250N46O41S8.
    CAS No.: 484598-36-9
    Activity ProTx-II inhibits NaV channels1. ProTx-II could also modulate T-type Ca2+ channels at higher concentrations2.
      • Middleton, R.E. et al. (2002) Biochemistry 41, 14734.

      • Hall, E.O. et al. (2010) FASEB J24, 608.14.

    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 (1000 X g 5 min).
    Storage of solutions Up to one week at 4°C or three months at -20°C.
      • Alomone Labs ProTx-II blocks human NaV1.5 current stably expressed in HEK-293 cells.
        hNaV1.5 currents were elicited by 50 ms voltage ramp from the holding potential of -100 mV to +60 mV, applied every 10 sec using whole-cell voltage clamp technique. Left: Superimposed traces of hNaV1.5 currents measured under control conditions and after 100 sec perfusion with 50, 100 and 200 nM ProTx-II (#STP-100), as indicated. Inset: Time course of hNaV1.5 current amplitude change as a result of 10, 25, 50, 100 and 200 nM ProTx-II application, as indicated by the horizontal bars. Right: ProTx-II dose response of hNaV1.5 currents (n = 3).
      • ProTx-II is a peptidyl toxin originally produced in Thrixopelma pruriens, the Peruvian green velvet tarantula. It was identified as a voltage-gated Na+ channel (NaV) blocker which inhibits both tetrodotoxin-sensitive and tetrodotoxin-resistant channels1.

        Binding of ProTx-II to an extracelluar domain of NaV channel, probably to a hydrophobic site3, inhibits current by shifting the channel activation to more positive potentials1-2.

        ProTx-II Inhibits NaV1.2, NaV1.3, NaV1.5 , NaV1.6 , NaV1.7 and, NaV1.8. It is a significantly more potent inhibitor against NaV1.7 than the other NaV channel subtypes1.

        ProTx-II was also found as an effective modulator which shifts the voltage dependence activity of T-type Ca2+ channel1.

    Target NaV channels and T-type Ca2+ channels
    Net Peptide Content: 100%
    Image & Title ProTx-II
    Alomone Labs ProTx-I and ProTx-II inhibit T-type CaV channels.ProTx-I (#STP-400) was applied to mouse thalamic neurons and ProTx-II (#STP-100) was tested on mouse DRGs. ProTx-I blocks native mouse CaV3.1 channel and recombinant human CaV3.1 channel currents similarly, and blocks to a lesser extent CaV3.2 and CaV3.3 channel currents. ProTx-II blocks CaV3.2 channels more potently than the other T-type currents.Adapted from Bladen, C. et al. (2014) Mol. Brain 7, 36. with permission of BioMed Central.
    Last update: 12/03/2019

    ProTx-II (#STP-100) is a highly pure, synthetic, and biologically active peptide toxin.

    For research purposes only, not for human use