Ionophore Antibiotics

Abstract

Ionophore antibiotics are compounds produced by microorganisms (mainly spore-forming bacteria) ; they act by specifically increasing the ion permeability of the cell membrane. In Vol. I of this series, the then well-known ionophore antibiotics valinomycin (Hunter and Schwartz, 1967 a), gramicidin (Hunter and Schwartz, 1967 c), nigericin (Shaw, 1967 a), and monactin (Shaw, 1967 b) were discussed. At that time it was recognized that an ionophore acts at the membrane level, but the mechanism by which it does so was still controversial. In the decade which has since elapsed, many new ionophores became available, and most of the details of their mechanism of action were elucidated. As it has turned out, medical and pharmaceutical applications of ionophores are limited, since the activity of ionophores is not restricted to microbial membranes. On the other hand, ionophores were found to be wonderful tools in biochemical research at the cellular or membrane level.