AA sequence: Pyr-Phe-Thr-Asn-Val-Ser-Cys7-Thr-Thr-Ser-Lys-Glu-Cys13-Trp-Ser-Val-Cys17-Gln-Arg-Leu-His-Asn-Thr-Ser-Arg-Gly-Lys-Cys28-Met-Asn-Lys-Lys-Cys33-Arg-Cys35-Tyr-Ser-OH
(Disulfide bonds between Cys7-Cys28, Cys13-Cys33, and Cys17-Cys35)
Length (aa): 37
Formula: C176H277N57O55S7
Molecular Weight: 4295.90 Da
Appearance: White lyophilized solid
Solubility: water and saline buffer
CAS number: 95751-30-7
Source: Synthetic
Purity rate: > 97%
Charybdotoxin
KCa2+ channel blocker
Charybdotoxin (ChTx) is a 37 amino acid peptide isolated from the venom of the scorpion Leiurus quinquestriatus hebraeus that blocks voltage-gated and large conductance Ca2+ activated K+ channels KCa1.1 in nanomolar concentrations (IC50~ 3 nM). This blockade causes hyperexcitability of the nervous system. The toxin reversibly blocks channel activity by interacting at the external pore of the channel protein with an apparent Kd of 2.1 nM. ChTX also blocks KCa3.1 (IC50 5 nM), Kv1.2 (IC50 14 nM), Kv1.3 (IC50 2.6 nM) and Kv1.6 (IC50 2 nM) channels.
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Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels.
Gimenez-Gallego G., et al. (1988) Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels. Proc. Natl. Acad. Sci. U.S.A. PMID:2453055
Mechanism of charybdotoxin block of a voltage-gated K+ channel.
Goldstein SA, Miller C. (1993) Mechanism of charybdotoxin block of a voltage-gated K+ channel. Biophys J. PMID:7506068
The charybdotoxin receptor of a Shaker K+ channel: peptide and channel residues mediating molecular recognition.
Goldstein SA, et al. (1994) The charybdotoxin receptor of a Shaker K+ channel: peptide and channel residues mediating molecular recognition. Neuron. PMID:7516689