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Ionophorous properties of narasin, a new polyether monocarboxylic acid antibiotic, in rat liver mitochondria

1977; Elsevier BV; Volume: 26; Issue: 15 Linguagem: Inglês

10.1016/0006-2952(77)90359-8

1873-2968

David T. Wong, David H. Berg, Robert H. Hamill, John R. Wilkinson,

Antibiotics Pharmacokinetics and Efficacy

Narasin, a new polyether monocarboxylic acid antibiotic, inhibits ATPase and reverses swelling and H+ release from liver mitochondria after induction of cation transport. Among alkali metal cations, narasin shows ionophorous activities with a selectivity of Na+ K+ = Rb+ Cs+ Li+. However, narasin also induces permeability of mitochondria to the non-noble gas cation, Tl+ and the polyatomic cation, NH4+. In fact, the polyether monocarboxylic acid ionophores, narasin and monensin, are more appropriate ionophores for NH4+ than for alkali cations. Narasin inhibits 50 per cent of the ATP hydrolysis activated by dinitrophenol, valinomycin-K+ and monazomycin-K+-NH4+ with ic50 values of 2.5, 200 and 13 nM respectively. The corresponding ic50 values for monensin are 7, 750 and 45 nM. The polyether monocarboxylic acid ionophores may play an important role in ionophore-producing organisms as NH4+ carriers.