Chemical. CAS 2001-95-8. Formula C54H90N6O18. MW 1111.32. Valinomycin is a cyclododecadepsipeptide antibiotic originially isolated from Streptomyces strains and displays antibacterial efficacy. Valinomycin a neutral ionophore that selectively transfers alkali metal ions via biological and synthetic lipid membranes. Valinomycin is widely used as a selective potassium K-selective ionophore over Na and is an important research tool for membrane and membrane vesicles studies. As ionophore valinomycin has found application as a biosensor to detect potassium K efflux. Valinomycin induces apoptosis in several cell types, including CHO cells, by stimulating potassium efflux and leading to phosphatidylserine membrane translocation, caspase-3 activation, inducing mitochondrial damage and oxidative stress. Valinomycin shows antitumor, antifungal, antiviral, insecticidal and antibacterial effects.