Transmembrane gradient of K+ ions as an energy source in the yeast Saccharomyces carlsbergensis.

In the presence of 100 mM glucose antimycin A inhibits the respiration of the yeast S. carlsbergensis by 94%, but does not affect the K+ efflux, Mn2+ influx or the synthesis of high molecular weight polyphosphate (HPP). Therefore phosphorylation at the respiratory chain level is not involved in HPP synthesis or Mn2+ accumulation. Zn2+ similar to Mn2+ induces K+ efflux and HPP synthesis, while Co2+ and Ni2+ fail to produce these effects. The extracellular K+ (1-5 mM KCl) completely inhibits the HPP synthesis and reduces Mn2+ uptake by 40%. NaCl (60 mM) inhibits the HPP synthesis by 28%. Nigericin, candicidin and FCCP plus valinomycin completely prevent the HPP synthesis. The prolonged accumulation of Zn2+ and Mn2+ is accompanied by HPP conversion into low molecular weight polyphosphate (LPP). The HPP synthesis in response to the K+ efflux may be regarded as a specific regulatory mechanism, which increases the energy efficiency of yeast metabolism.