Name: ProTx-II
Brand: Alomone Labs
SKU: STP-100

Overview

Cat #: STP-100

Alternative Name β/ω-Theraphotoxin-Tp2a, Protoxin-2, PT-II, ProTx2, Protoxin2, ProTx II

Lyophilized Powder yes

Origin 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.

Structure

Molecular formula C₁₆₈H₂₅₀N₄₆O₄₁S₈.

CAS No.: 484598-36-9

Activity ProTx-II inhibits Na_V channels¹. ProTx-II could also modulate T-type Ca²⁺ channels at higher concentrations².

References-Activity

Middleton, R.E. et al. (2002) Biochemistry 41, 14734.
Hall, E.O. et al. (2010) FASEB J. 24, 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.

Our bioassay

Alomone Labs ProTx-II blocks human Na_V1.5 current stably expressed in HEK-293 cells.
hNa_V1.5 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 hNa_V1.5 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 hNa_V1.5 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 hNa_V1.5 currents (n = 3).

References - Scientific background

Middleton, R.E. et al. (2002) Biochemistry 41, 14734.
Smith, J.J. et al. (2005) J. Biol. Chem. 280, 11127.
Smith, J.J. et al. (2007) J. Biol. Chem. 282, 12687.

Scientific background

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 (Na_V) blocker which inhibits both tetrodotoxin-sensitive and tetrodotoxin-resistant channels¹.

Binding of ProTx-II to an extracellular domain of Na_V channel, probably to a hydrophobic site³, inhibits current by shifting the channel activation to more positive potentials^1-2.

ProTx-II Inhibits Na_V1.2, Na_V1.3, Na_V1.5, Na_V1.6, Na_V1.7, and Na_V1.8. It is a significantly more potent inhibitor against Na_V1.7 than the other Na_V channel subtypes¹.

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

Target Na_V channels and T-type Ca²⁺ channels

Peptide Content: 100%

Lyophilized Powder

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

Certificate of Analysis SDS

Image & Title

Alomone Labs ProTx-I and ProTx-II inhibit T-type Ca_V 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 Ca_V3.1 channel and recombinant human Ca_V3.1 channel currents similarly, and blocks to a lesser extent Ca_V3.2 and Ca_V3.3 channel currents. ProTx-II blocks Ca_V3.2 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.

For research purposes only, not for human use

Last Update: 10/04/2023

Applications

Citations

Product citations

Salari, A. et al. (2016) Sci. Rep. 6, 1.
Bladen, C. et al. (2014) Mol. Brain 7, 36.

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ProTx-II

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