IMMUNOASSAY OF POLYPHOSPHATASES FROM DIFFERENT COMPARTMENTS OF SACCHAROMYCES-CEREVISIAE YEAST-CELLS

Antibodies against purified cell-envelope polyphosphatase of Saccharom yces cerevisiae inhibited the activity both of this and of cytosol pol yphosphatases and did not affect the polphosphatases of vacuoles and n uclei isolated from the same yeast. Using immunoblotting, it has been shown that it is the 40-kD polypeptide that binds to these antibodies in preparations of cell-envelope and partially purified cytosol polyph osphatase. The molecular weights of these polypeptides determined by o ther methods were almost identical. In the vacuolar preparation, the p olypeptides of 72 and 40 kD reacted with antibodies, while in the nucl ear preparation, those of 64 and 32 kD.