Polyphosphatase PPN1 of Saccharomyces cerevisiae: Switching of Exopolyphosphatase and Endopolyphosphatase Activities

The polyphosphatase PPN1 of Saccharomyces cerevisiae shows an exopolyphosphatase activity splitting phosphate from chain end and an endopolyphosphatase activity fragmenting high molecular inorganic polyphosphates into shorter polymers. We revealed the compounds switching these activities of PPN1. Phosphate release and fragmentation of high molecular polyphosphate prevailed in the presence of Co(2+) and Mg(2+), respectively. Phosphate release and polyphosphate chain shortening in the presence of Co(2+) were inhibited by ADP but not affected by ATP and argininе. The polyphosphate chain shortening in the presence of Mg(2+) was activated by ADP and arginine but inhibited by ATP.