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µ-Conotoxin GIIIB

Myotoxin II, Geographutoxin II, GTx-II

A Selective Blocker of Skeletal Muscle NaV1.4 Channels

Cat #: C-270
Alternative Name Myotoxin II, Geographutoxin II, GTx-II
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Synthetic peptide
    MW: 2640 Da
    Purity: >99% (HPLC)
    Effective concentration 100-600 nM.
    Modifications Disulfide bonds between Cys3-Cys15, Cys4-Cys20, and Cys10-Cys21. X = 4-Hydroxyproline. Ala22 - C-terminal amidation.
    Molecular formula C101H175N39O30S7.
    CAS No.: 140678-12-2
    Activity μ-Conotoxin GIIIB binds and blocks site 1 of voltage-gated Na+ channels1.
    1. Cruz, L.J. et al. (1985) J. Biol. Chem. 260, 9280.
    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 (10000 x g 5 min).
    Storage of solutions Up to one week at 4°C or three months at -20°C.
    Our bioassay
    • Alomone Labs μ-Conotoxin GIIIB inhibits NaV1.4 channels heterologously expressed in Xenopus oocytes.
      Alomone Labs μ-Conotoxin GIIIB inhibits NaV1.4 channels heterologously expressed in Xenopus oocytes.
      100 nM μ-Conotoxin GIIIB (#C-270) inhibited Nacurrents. Holding potential was -100 mV and test pulses of 25 ms to -20 mV were delivered every 5 sec. Left: Time course of current inhibition by toxin and recovery. The bar represents period of toxin perfusion. Right: Superimposed traces of NaV1.4 current before (black) and during (orange) application of μ-Conotoxin GIIIB.
    References - Scientific background
    1. Cruz, L.J. et al. (1985) J. Biol. Chem260, 9280.
    2. Li, R.A. et al. (2003) J. Biol. Chem278, 8717.
    3. Filatov, G.N. and Rich, M.M. (2004) J. Physiol. 559, 813.
    4. Robitaille, R. and Charlton, M.P. (1992) J. Neurosci. 12, 297.
    Scientific background µ-Conotoxin GIIIB was originally isolated from the marine snail Conus geographus. The peptide toxin selectively blocks NaV1.4 channels, which are expressed predominantly in skeletal muscle.1,2 It is a potent blocker and 600 nM completely blocked NaV1.4-related currents in rat skeletal muscle.3
    Target NaV1.4 Na+ channels
    Peptide Content: 100%
    Image & Title

    µ-Conotoxin GIIIBEDL muscle fibers from SBMA mice show reduced sensitivity to µ-Conotoxin GIIIB.Traces of action potentials before and after incubation in 2.5 µM µ-Conotoxin GIIIB (#C-270) for 30 minutes. Potentials were blocked in WT fibers (left) but not in diseased fibers (right).Adapted from Xu, Y. et al. (2016) J. Neurosci. 36, 5094. with permission of The Society for Neuroscience.

    Last update: 06/11/2022

    µ-Conotoxin GIIIB (#C-270) is a highly pure, synthetic, and biologically active peptide toxin.

    For research purposes only, not for human use



    Product citations
    1. Bradford, A.B. et al. (2018) Toxicol. Appl. Pharmacol. 341, 77.
    2. Chand, K.K. et al. (2018) FASEB J. 32, 2676.
    3. Laghaei, R. et al. (2018) J. Neurophysiol. 119, 1340.
    4. Wang, X. et al. (2018) J. Neurosci. 38, 1725.
    5. Wu, M. et al. (2018) Neuropharmacology 131, 176.
    6. Bertone, N.I. et al. (2017) Synapse 71, e2209.
    7. Hurtado, E. et al. (2017) Front. Mol. Neurosci. 10, 147.
    8. Hurtado, E. et al. (2017) Front. Mol. Neurosci. 10, 270.
    9. Ng, F. et al. (2017) Muscle Nerve 55, 223.
    10. Zanetti, G. et al. (2017) PLoS Pathog. 13, e1006567.
    11. Bronnimann, D. et al. (2016) PLoS ONE 11, e0150948.
    12. Ouanounou, G. et al. (2016) eLife 5, e12190.
    13. Spaulding, E.L. et al. (2016) J. Neurosci. 36, 3254.
    14. Willadt, S. et al. (2016) Sci. Rep. 6, 24849.
    15. Xu, Y. et al. (2016) J. Neurosci. 36, 5094.
    16. Duregottia, E. et al. (2015) Proc. Natl. Acad. Sci. USA. 112, E497.
    17. Wu, Y.J. et al. (2015) J. Neurophysiol. 114, 2404.
    18. Ruiz, R. et al. (2014) Neuropharmacology 76, 106.
    19. Ackermann, Bet al. (2013) Hum. Mol. Genet. 22, 1328.
    20. Baskaran, P. et al. (2013) Toxicon 72, 71.
    21. Krieger, Fet al. (2013) Neurobiol. Dis. 54, 169.
    22. Rodrigues, H.A. et al. (2013) PLoS ONE 8, e78342.
    23. Tarr, T.B. et al. (2013) J. Neurosci. 33, 10559.


    Scientific Background

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