Name: Vm24 Toxin
Brand: Alomone Labs
SKU: STV-055

Overview

Cat #: STV-055

Alternative Name alpha-KTx 23.1, Potassium channel toxin alpha-KTx 23.1

Lyophilized Powder yes

Origin Vaejovis mexicanus smithi, (Mexican scorpion)

Source Synthetic peptide

MW: 3864 Da

Purity: ≥98%

Form Lyophilized Powder

Effective concentration 3-10 pM

Sequence AAAISCVGSPECPPKCRAQGCKNGKCMNRKCKCYYC-NH₂

Modifications Cys³⁶: C-terminal amidation
Disulfide bonds location - Cys⁶-Cys²⁶, Cys¹²-Cys³¹, Cys¹⁶-Cys³³, Cys²¹-Cys³⁶

Structure

Molecular formula C₁₅₇H₂₅₃N₅₁O₄₅S₉

Activity Vm24 toxin is a potent and selective K_v1.3 channel blocker (Kd ∼ 3 pM)¹. This toxin exhibits more than 1500-fold selectivity for Kv1.3 over KCa3.1, Kv1.1, and Kv1.2 and does not inhibit a wide range of other channels². Vm24 inhibits the proliferation and Ca²⁺ signaling of human T cells in vitro and reduces delayed-type hypersensitivity reactions in rats in vivo².

References-Activity

Gurrola, G.B. et al. (2012) Biochemistry, 51, 4049.
Varga, Z. et al. (2012) Mol Pharmacol., 82, 372.

Accession number

P0DJ31

Shipping and storage The product is shipped as a lyophilized powder at room temperature. Upon receipt, it should be stored at -20°C. Protect from moisture.

Solubility Soluble in water. For long-term storage in solution, we recommend to prepare a stock solution by dissolving the product in ddH₂O at a concentration X100-1000 of final working solution. Divide the solution into small aliquots and store at -20°C. Upon use, thaw the relevant vial intended for use and dilute in your desired working buffer. Centrifuge all product preparations before use (10000 x g, 5 min). Repeated freeze-thawing might result in loss of activity. [It is recommended to prepare working solutions fresh before use].

Storage of solutions The reconstituted solution can be stored at 4°C for up to 1 week. For longer periods (up to 6 months), small aliquots should be stored at -20°C. We do not recommend storing the toxin in working solutions for longer than a few days. Avoid multiple freeze- thawing cycles.

Our bioassay

Alomone Labs Vm24 blocks K_V1.3 channels expressed in Xenopus oocytes.
A. Representative time course of Vm24 (#STV-055) inhibition of normalized K_V1.3 current. Membrane potential was held at -80 mV, current was elicited by a 100 ms voltage ramp to +60 mV every 10 sec, and significantly inhibited by 10 pM (green) Vm24.
B. Superimposed traces of K_V1.3 channel currents in the absence (control) and presence of 10 pM (green) Vm24 (taken from the recording in A).

References - Scientific background

Gurrola, G.B. et al. (2012) Biochemistry, 51, 4049.
Varga, Z. et al. (2012) Mol Pharmacol., 82, 372.
Hu, T. et al. (2019) Oncotarget. 10, 4894.
Veytia-Bucheli, J.I. et al. (2018) Cell Commun Signal., 16, 45.
Revuelta, M. et al. (2022) Front Cell Neurosci., 16, 868842.

Scientific background

The Vm24 toxin, also known as Vaejovis mexicanus peptide 24, is a potent blocker of K_v1.3 in human lymphocytes. Isolated from the venom of the Mexican scorpion Vaejovis mexicanus smithi, Vm24 is a 36-residue peptide with a molecular mass of 3864 Da, and has been identified as the first example of a new subfamily of α-type K(+) ion channel blockers (α-KTx 23.1)¹.

Vm24, a natural immunosuppressive peptide, potently and selectively blocks K_v1.3 in human T cells with high affinity. The blockage of K_v1.3 channels in T cells is a promising therapeutic approach for the treatment of autoimmune diseases such as multiple sclerosis and type 1 diabetes mellitus².

The voltage-gated potassium channel known as K_v1.3 (KCNA3) is expressed by a subset of chronically activated memory T cells and plays an important role in their activation and proliferation, especially in primary malignant T cells. The potent K_v1.3 inhibitor Vm24 inhibits CD3/CD28-induced proliferation and IL-9 expression, thus inhibiting activation-induced proliferation as well as cytokine and cytokine receptor expression in malignant T cells³.

Due to its high specificity, the Vm24 toxin enables to define the downstream functions of K_v1.3 channels in human CD4+ TEM lymphocytes. Blocking Kv1.3 channels profoundly affects the mRNA synthesis machinery, the unfolded protein response and intracellular vesicle transport, impairing the synthesis and secretion of cytokines in response to TCR engagement. This underscores the role of K_v1.3 channels in regulating TEM lymphocyte function⁴.

K_V1.3 blockers change the course of Alzheimer's Disease (AD) development, reducing microglial cytotoxic activation and increasing neural stem cell differentiation. K_V1.3 blockers inhibit microglia-mediated neurotoxicity in cell cultures, reducing the expression and production of the pro-inflammatory cytokines IL-1β and TNF-α via the NF-kB and p38MAPK pathway. Microglia activation correlates with an increase in KV1.3 channel expression and current density. Several studies highlight the importance of K_V1.3 in the activation of the inflammatory response and the inhibition of neural progenitor cell proliferation and neuronal differentiation. Thus, K_V1.3 blockers such as Vm24 possess potential therapeutic benefits for patients suffering from Alzheimer’s disease⁵

Target K_v1.3 channels

Peptide Content: 100%

Lyophilized Powder

Vm24 Toxin (#STV-055) is a highly pure, synthetic, and biologically active peptide toxin.

Certificate of Analysis SDS

For research purposes only, not for human use

Last Update: 07/05/2024

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Vm24 Toxin

Overview

P0DJ31

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Citations

Specifications

Scientific Background

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