Valinomycin is an antibiotic that are mainly used against the bacteria streptomycin. The valinomycin might also acts as the ionophore used for the regulation of the ions transport.
Only some selected particles can pass down to the plasma membrane. The hydrophobic molecule can easily cross the plasma membrane. Valinomycin is hydrophobic on its exterior surface and easily diffuse through the cell membrane. Valinomycin is hydrophillic from the interior surface and used for the encapsulation of the polar ions.