Changes in energy charge and block of protein synthesis in rabbit reticulocytes under the action of valinomycin.

Valinomycin blocks protein synthesis at the elongation stage in intact reticulocyte while being without action on a cell free system. We demonstrate here that this membrane mediated inhibition is accompanied by a change of the energy charge (ATP/ADP/AMP ratio) of the cells. There seems to be an accumulation of AMP without a proportional gain in ADP. The change in energy charge in itself can be the cause of the inhibition of protein synthesis. We show also that valinomycin can cause a decrease of the energy charge at concentrations where its action as an ionophore is not seen and independent of a possible activation of the Na-K dependent ATPase.