Valinomycin

Valinomycin is a cyclododecadepsipeptide potassium-selective ionophore. It is an antibiotic that was originially isolated from various strains of Streptomyces. The hydrophilic interior is the right size to accommodate the potassium ion, but not other ions, while the hydrophobic exterior allows the complex to pass through the lipid bilayer. Valinomycin induces apoptosis in several cell types, including CHO cells, by stimulating potassium efflux. Apoptotic events produced by valinomycin include phosphatidylserine membrane translocation, caspase-3 activation, and mitochondrial membrane depolarization. Due to the ion-selective nature of valinomycin, it is used in ion-selective electrodes.