with the brush border membrane vesicles prepared from the rat kidney cortex , didemnin b and its parent compound , didemnin a function neither as a k+-specific ionophore nor as an ionophore for na+ ions while other depsipeptide antibiotics such as valinomycin and gramicidin promote transmembrane movement of k+ and na+ ions , respectively .
C0796678
depsipeptide
C0042287
valinomycin