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Hm1b Toxin

Delta-theraphotoxin-Hm1b, Delta-TRTX-Hm1b, δ-theraphotoxin-Hm1b

An Activator of Nav1.1 and Nav1.3 Channels

Cat #: STH-655
Alternative Name Delta-theraphotoxin-Hm1b, Delta-TRTX-Hm1b, δ-theraphotoxin-Hm1b
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Heteroscodra maculata (Togo starburst tarantula)
    Source Synthetic peptide
    MW: 3895.4 Da
    Purity: >98%
    Form Lyophilized Powder
    Effective concentration 20-500 nM
    Modifications Disulfide bonds between: Cys2-Cys16, Cys9-Cys21 and Cys15-Cys28
    Molecular formula C169H241N45O50S6
    Activity Hm1b acts as a potent and highly selective activator of NaV1.1 and NaV1.3 voltage-gated sodium channels1.
    1. Chow, C.Y. et al. (2020) Biochem. Pharm., 181, 113991.
    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 Soluble in DDW.
    Centrifuge all products before use (10000 x, g 5 min). Avoid multiple freezing and thawing.
    Storage of solutions Store at 4°C for up to 1 week. For longer periods, small aliquots should be stored at -20°C.
    Our bioassay
    •  Alomone Labs Hm1b toxin enhances the current of NaV1.1 channels expressed in Xenopus oocytes.
      Alomone Labs Hm1b toxin enhances the current of NaV1.1 channels expressed in Xenopus oocytes.
      A. Representative time course of Hm1b Toxin (#STH-655) effect on the normalized area of NaV1.1 channels current. Membrane potential was held at -100 mV, current was elicited by a 100 ms voltage step to 0 mV every 10 sec, and was significantly enhanced by the application of 100 nM Hm1b (green). B. Superimposed traces of NaV1.1 current after application of control (black) and of 100 nM Hm1b toxin (green), taken from the recording in A.
    References - Scientific background
    1. Osteen, J.D. et al. (2016) Nature 534, 494.
    2. Chow, C.Y. et al. (2020) Biochem. Pharm. 181, 113991
    Scientific background

    δ-theraphotoxin-Hm1b (Hm1b) is a 34 amino acid peptidyl toxin originally isolated from the venom of the tarantula, Heteroscodra maculata1. Hm1b acts as a potent and highly selective activator of the voltage-gated sodium (NaV) 1.1 and NaV1.3 channels. This toxin inhibits the inactivation of the human NaV1.1 channel (expressed in HEK293 cells) with an EC  value of 12 nM1,2.

    The Hm1b toxin has a high level of sequence similarity to the Hm1a toxin, which is also a selective and specific activator of NaV1.1 channels. Both toxins are members of the extended family of inhibitor cystine knot (ICK) peptides with C1–C4, C2–C5, and C3–C6 disulfide architecture. In addition, they share secondary structure characteristics, specifically an antiparallel β hairpin. Despite the high degree of sequence similarity between Hm1a and Hm1b, the latter is much more stable in biological fluids2.

    NaV channels are involved in a wide array of physiological processes and play a fundamental role in normal neurological function, especially in the initiation and propagation of action potentials. NaV1.1 channel has been utilized as a therapeutic target for various brain disorders, including epilepsy, Alzheimer's disease, and autism. The NaV1.1 channel also contributes to mechanical pain by regulating the excitability of a specific subset of sensory neurons within the peripheral nervous system.

    Target NaV1.1, Nav1.3, Voltage-gated Na+ channels
    Net Peptide Content: 100%
    Last update: 11/04/2021

    Hm1b Toxin (#STH-655) is a highly pure, synthetic, and biologically active peptide toxin.

    For research purposes only, not for human use
    Shipping and Ordering information