Purified cell-envelope polyphosphatase as well as polyphosphatase acti
vities of cytosol and isolated vacuoles, of nuclei and mitochondria of
the yeast Saccharomyces cerevisiae were compared. The polyphosphatase
s of cell envelope and cytosol are similar, the polyphosphatases of nu
clei, vacuoles and mitochondria differ in their kinetic properties, su
bstrate specificity, requirements in divalent cations and in some effe
ctor actions both from these and from each other.