a blocker of Ca²⁺-activated K⁺ channels of high conductance and some voltage-dependent K⁺ channels; in human and murin blymphocytes, where both K⁺ channels subtypes are present, Kaliotoxin is a selective voltage-dependent K⁺ channels blocker.

38-amino acid peptide with 3 disulfide bridges. Synthetic, originally from Androctonus mauretanicus mauretanicus scorpion venom.

• Molecular Weight : 4,150.0 Da.
  
  
• Solubility in : well in water and saline.
  
  
• Purity min. : 98 % (HPLC, mass spectrometry).
  
  
• Biological Activity : Neurons: KTX blocks the invertebrate and mammalian sympathetic high conductance K⁺ channels with a Kd of 2 to 4 nM. These effects were observed on the whole-cell current as well as on the unitary channel activity.
  KTX inhibits the shaker K⁺ current resulting from mRNA expression in Xenopus oocyte with a Kd of 2 to 5 nM.
  The radiolabelled derivative 125I KTX binds to the rat brain synaptosomal membrane (Kd = 10 pM) and it is displaced by Dendrotoxin with a Kd of 8 pM.
  
  Muscle: KTX is poorly active on skeletal high conductance K⁺ channels incorporated in lipid bilayers.
  
  Lymphocytes: in human and murin b-lymphocytes, where both Ca²⁺-activated K⁺ channels and voltage-dependent K⁺ channels are present, KTX selectively inhibits the activity of the voltage-dependent K⁺ channels with a Kd of 1 to 5 nM.
  
  
• Toxicity (LD₅₀) : mice (intracerebroventricularly): 1.20 to 1.55 µg/kg.
  
  
• Storage recommendations : stable in freeze-dried state. In solution, keep at -20 °C.
  
  
• CAS Reg. No. : 145199-73-1
  
  
• Bibliography :
  
  1. Crest et al., "Kaliotoxin, a novel peptidyl inhibitor of neuronal BK-type Ca²⁺-activated K⁺ channels characterized from Androctonus mauretanicus mauretanicus venom." J. Biol. Chem. (1992). 267(3):1640-1647