Characterization of PO1, a new peptide ligand of the apamin-sensitive Ca2+ activated K+ channel.

A new peptide ligand of the small conductance Ca2+ activated K+ channels has been purified from the venom (obtained by manual rather than electrical stimulation of the scorpion Androctonus mauretanicus mauretanicus), by following the inhibition of the 125I-apamin binding to its receptor on rat brain synaptosomes. Only one step on a C18 reversed-phase high-performance liquid chromatography column was necessary to obtain PO1. Its K0.

Growth inhibition of Trypanosoma cruzi and Leishmania donovani infantum by different snake venoms: preliminary identification of proteins from Cerastes cerastes venom which interact with the parasites.

Venom from three different snake species was tested in vitro against the protozoan parasites Trypanosoma cruzi and Leishmania donovani infantum. Two of them, Cerastes cerastes and Naja haje, exerted a significant growth inhibition of T. cruzi and L.

Synthesis and characterization of kaliotoxin. Is the 26-32 sequence essential for potassium channel recognition?

Kaliotoxin (KTX), a scorpion toxin characterized as a 37-residue inhibitor of the neuronal high conductance Ca(2+)-activated K+ channels (KCa channels), has been chemically synthetized. Differences were observed between natural toxin and the two peptides, KTX(1-37) and KTX(1-37)-amide. Re-examination of the KTX sequence showed that an extra lysine residue was present at the C-terminal end.

Characterization of a new leiurotoxin I-like scorpion toxin. PO5 from Androctonus mauretanicus mauretanicus.

Three novel peptide inhibitors of the SKCa channels were purified to homogeneity from the venom of the scorpion Androctonus mauretanicus mauretanicus using one step of RP-HPLC and competition assays with [125I]apamin to rat brain synaptosomes. PO1, PO2 and PO5 have K0.5 of 100, 100 and 0.