ProTx-I
Based on 1 Customer Validation
ProTx-I is a toxin derived from Thrixopelma pruriens and a peptide inhibitor targeting TTX-resistant sodium channels. ProTx-I interacts with voltage sensors of multiple domains such as NaV1.7, reduces neuronal excitability through allosteric modulation of channel gating and alteration of voltage dependence. The IC50 values of ProTx-I against human NaV1.7, NaV1.2, NaV1.6, and NaV1.5 are 95 nM, 104 nM, 21 nM, and 358 nM, respectively; ProTx-I also potently inhibits Ba2+ currents of hCav3.1, while its inhibitory potency against hCav3.2 is approximately 160-fold lower. ProTx-I is applicable to the research of chronic pain.
For research use only. We do not sell to patients.
- Purity : 99.80%
- CAS No.: 484598-35-8
- Formula: C171H245N53O47S6
- Molecular Weight:3987.49
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Storage:
Sealed storage, away from moisture.
Powder -80°C, 2 years , -20°C, 1 year* In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture)
All Calcium Channel Isoforms
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Biological Activity
Description
IC50 & Target
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T-type calcium channel |
Nav1.2 104 nM (IC50) |
Nav1.6 21 nM (IC50) |
Nav1.7 95 nM (IC50) |
KV2.1 411 nM (IC50) |
TRPA1 389 nM (IC50) |
hNav1.5 358 nM (IC50) |
In Vitro
ProTx-I (0.01-10 μM; ~7-30 min) potently inhibits Ba2+ currents through hCav3.1-expressing Xenopus laevis oocytes with an IC50 of 0.20 μM, causes voltage-dependent inhibition and a small positive shift in activation potential, and exhibits partial to nearly irreversible binding[2].
ProTx-I (0.1-10 μM; ~2-7 min) weakly inhibits Ba2+ currents through hCav3.2-expressing Xenopus laevis oocytes with an IC50 of 31.8 μM, does not alter channel activation properties, and exhibits fully reversible binding[2].
ProTx-I (multiple concentrations) shows drastically reduced sensitivity when the domain IV S3-S4 linker of hCav3.1 is replaced with that of hCav3.2, resulting in an IC50 of 17.8 μM in hCav3.1/S3S4-expressing Xenopus laevis oocytes[2].
ProTx-I (multiple concentrations) shows increased sensitivity when the domain IV S3-S4 linker of hCav3.2 is replaced with that of hCav3.1, resulting in an IC50 of 15.8 μM in hCav3.2/S3S4-expressing Xenopus laevis oocytes[2].
ProTx-I (70 nM) inhibits heterologously expressed Cav3.1 voltage-gated calcium channels by shifting their voltage dependence of activation to more positive potentials, with an apparent IC50 of 70 nM during weak depolarizations[3].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only. Further protocols information, click here.
Chemical Information
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CAS No. 484598-35-8
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Appearance Solid
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Molecular Weight 3987.49
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Formula C171H245N53O47S6
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Color White to off-white
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Sequence
Glu-Cys-Arg-Tyr-Trp-Leu-Gly-Gly-Cys-Ser-Ala-Gly-Gln-Thr-Cys-Cys-Lys-His-Leu-Val-Cys-Ser-Arg-Arg-His-Gly-Trp-Cys-Val-Trp-Asp-Gly-Thr-Phe-Ser (Disulfide bridge:Cys2-Cys16;Cys9-Cys21;Cys15-Cys28)
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Sequence Shortening
ECRYWLGGCSAGQTCCKHLVCSRRHGWCVWDGTFS (Disulfide bridge:Cys2-Cys16;Cys9-Cys21;Cys15-Cys28)
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Shipping
Room temperature in continental US; may vary elsewhere.
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Storage
Sealed storage, away from moisture
Powder -80°C 2 years -20°C 1 year * In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture)
Solvent & Solubility
In Vitro:
DMSO : 25 mg/mL (6.27 mM; Need ultrasonic; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO)
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
Concentration (start) × Volume (start) = Concentration (final) × Volume (final)
Protocols
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Cell Cytotoxicity Assay
Cytotoxicity assays are usually based on the assessment of cell membrane damage, which can also be indirectly detected by measuring cell viability. Detection methods include MTT assay, CKK-8 assay, LDH assay and ATP assay, etc.
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Neuronal voltage-sensitive dye imaging
Neuronal voltage-sensitive dye imaging detects membrane-potential-dependent optical changes from dyes associated with neuronal membranes, enabling optical recording of electrical activity from single neurons, dendrites, axons, spines, or neuronal populations in brain slices and cultured neurons. VSD signals are typically reported as fractional fluorescence or absorbance changes over baseline, such as ΔF/F or ΔI/I, and published protocols use high-speed cameras or photodiode arrays because neuronal voltage signals occur on millisecond time scales. Fast VSD imaging can be applied at two common scales: bulk staining of brain slices to measure circuit-level spatiotemporal activity, and single-cell loading or biolistic delivery to record membrane-potential transients from individual neuronal compartments. Optical signals should be interpreted as membrane-potential-related readouts, and validation by simultaneous electrophysiology or pharmacological controls is recommended when the experimen
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Cell-attached patch-clamp recording
Cell-attached patch-clamp recording measures ionic current through one or more ion channels in a small membrane patch that remains attached to an intact cell; the readout is a time-resolved current trace generated when channels in the sealed patch open and close under controlled pipette voltage or stimulus conditions. Classic applications include single acetylcholine receptor currents in frog skeletal muscle, single sodium-channel currents in cultured rat muscle cells, one-channel NMDA receptor recordings, and mechanically activated PIEZO-channel recordings. The method depends on forming a high-resistance pipette-membrane seal, commonly described as a gigaohm seal, which reduces leak and noise sufficiently to resolve picoampere-scale single-channel currents. In the cell-attached configuration, the patch membrane is not ruptured, so cytosolic composition is not directly dialyzed by the pipette solution.
Purity & Documentation
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Data Sheet (297 KB)
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SDS (254 KB)
- English - EN (254 KB)
- Français - FR (254 KB)
- Deutsch - DE (254 KB)
- Norwegian - NO (254 KB)
- Español - ES (254 KB)
- Swedish - SV (254 KB)
- Italian - IT (254 KB)
- Korean - KR (254 KB)
- Portuguese - PT (254 KB)
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Handling Instructions (2659 KB)
References
[1]. Rupasinghe DB, et al. Mutational analysis of ProTx-I and the novel venom peptide Pe1b provide insight into residues responsible for selective inhibition of the analgesic drug target NaV1.7. Biochem Pharmacol. 2020;181:114080. [Content Brief]
[2]. Ohkubo T, et al. Tarantula toxin ProTx-I differentiates between human T-type voltage-gated Ca2+ Channels Cav3.1 and Cav3.2. J Pharmacol Sci. 2010;112(4):452-458. [Content Brief]
[3]. Priest BT, et al. ProTx-I and ProTx-II: gating modifiers of voltage-gated sodium channels. Toxicon. 2007;49(2):194-201. [Content Brief]
Complete Stock Solution Preparation Table
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
| Optional Solvent | Concentration Solvent Mass | 1 mg | 5 mg | 10 mg | 25 mg |
|---|---|---|---|---|---|
| DMSO | 1 mM | 0.2508 mL | 1.2539 mL | 2.5078 mL | 6.2696 mL |
| 5 mM | 0.0502 mL | 0.2508 mL | 0.5016 mL | 1.2539 mL |