Iberiotoxin; Buthus tamulus; Recombinant; E. coli

Biochem/physiol Actions

Cell permeable: no

Reversible: yes

Product does not compete with ATP.

Primary TargetHigh conductance Ca2+-activated K+ channels

potently inhibits Ca²⁺-activated K⁺ channels expressed in Xenopus oocytes

Target IC₅₀: 250 pM against high conductance Ca2+-activated K+ channels

General description

Recombinant Buthus tamulus iberiotoxin expressed in E. coli. A single polypeptide chain of 37 amino acids that displays about 68% sequence homology with charybdotoxin (ChTx). Acts as a selective, reversible blocker of high conductance, Ca²⁺-activated K⁺ channels (PK,Ca). rIbTx does not block other types of voltage-dependent ion channels, especially other types of K⁺ channels that are sensitive to inhibition by ChTx. Shown to block PK,Ca in excised membrane patches from bovine aortic smooth muscle, acting exclusively at the outer face of the channel (IC₅₀ = 250 pM). Causes a decrease in probability of channel opening and the channel open mean time. rIbTx appears to modulate ChTx binding by an allosteric mechanism.

Recombinant Buthus tamulus iberiotoxin expressed in E. coli. Acts as a selective, reversible blocker of high conductance Ca²⁺-activated K⁺ channels (IC₅₀ = 250 pM).

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Other Notes

Vanelli, G., et al. 1994. J. Appl. Physiol.76, 1098.Garcia, M.L., et al. 1991. J. Bioeng. Biomembr.23, 615.Galvez, A., et al. 1990. J. Biol. Chem. 265, 11083.

Packaging

10 µg in Plastic ampoule

Reconstitution

Following reconstitution, aliquot and freeze (-20°C) for long-term storage or refrigerate (4°C) for short-term storage. Stock solutions are stable for up to 3 months at -20°C or up to 2 weeks at 4°C.

Reconstitute in Tris-buffered saline (100 mM NaCl, 10 mM Tris-HCl, pH 7.5) containing 0.1% BSA.

Sequence

Pyr-Phe-Thr-Asp-Val-Asp-Cys⁷-Ser-Val-Ser-Lys-Glu-Cys¹³-Trp-Ser-Val-Cys¹⁷-Lys-Asp-Leu-Phe-Gly-Val-Asp-Arg-Gly-Lys-Cys²⁸-Met-Gly-Lys-Lys-Cys³³-Arg-Cys³⁵-Tyr-Gln-OH (disulfide bonds: 7 →28; 13 → 35; 17 → 33)

Warning

Toxicity: Harmful (C)