Localization of divalent cations in phosphate‐rich cytoplasmic granules in yeast

Abstract Phosphate‐rich yeast cells (Saccharomyces cerevisiae) take up more calcium and strontium than phosphate‐deficient cells. The divalent cations appear to be tightly bound in phosphate‐rich cells. Electron microscopical investigations, combined with energy‐dispersive X‐ray microanalysis, showed that divalent cations were sequestered in cytoplasmic granules, together with a large amount of phosphorus. The major part of the divalent cations is retrieved in the polyphosphate fraction, a minor part is bound to lipids. The results suggest that polyphosphate granules may serve as an important store for divalent cations.