rIberiotoxin

rIberiotoxin

A Potent and Specific Blocker of K_Ca1.1 (BK, slo, Large Conductance Ca²⁺ Dependent K⁺) Channels

Product#:

RTI-400

Sizes:

5 mg

5 x 5 mg

10 mg

5 x 10 mg

0.1 mg

Iberiotoxin was originally isolated from the scorpion Mesobuthus tamulus and was shown to block large conductance Ca²⁺ activated K⁺ channels in smooth muscle cells.¹ Later it was shown to specifically block K_Ca1.1 (Slo) channels with K_i of about 1 nM.² In addition, experiments with cloned K_Ca1.1 channels demonstrate the strong effect of the slob subunits on the potency of block by Iberiotoxin (see for example³).

M.W.:

4248

Sequence:

EFTDV DCSVS KECWS VCKDL FGVDR GKCMG KKCRC YQ

Purity:

>99%

Bioassay:

Recombinant Iberiotoxin was tested to confirm its ability to potently inhibit KCa1.1 channels (mSlo) expressed in Xenopus oocytes. The IC50 in this assay was 1 nM.

KCa1.1 channel currents (5 mM K+) from Xenopus oocytes, before and during application of 100 nM rIberiotoxin. Holding potential, -100 mV, test potential, +50 mV for 100 ms. The vertical bar represents 0.1 mA.

References:

1.	Galvez, A. et al. (1990) J. Biol. Chem. 265, 11083.
2.	Koschak, A. et al. (1997) Biochemistry 36, 1943.
3.	Meera, P. et al. (2000) Proc. Natl. Acad. Sci. USA. 97, 5562.