C54H90N6O18. Cyclododecadepespipeptide neutral ionophore produced by Streptomyces fulvissimus. Composed of 3 moles each of L-valine, D- a-hydroxyisovaleric acid, D-valine, and L-lactic acid linked to form a 36-member ring from the 12 constituent molecules. This molecule has great flexibility in solution but gains marked structure when it complexes potassium, K+, with the 6 carbonyl oxygens from the acids; two additional oxygens from water may coordinate with the K+ to give a coordination number of 8. The 9 isopropyl groups and 3 methyl groups give this molecule low solubility in water but relatively high solubility in ether, benzene, chloroform, and lipids. The high affinity for potassium gives this compound utility as an antibiotic, an insecticide, a nematodicide, and an ionophore in K+-specific electrodes.

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