Hydrolysis of nucleoside di- and triphosphates by crystalline preparations of yeast inorganic pyrophosphatase

Abstract

1. 1. Crystalline preparations of yeast inorganic pyrophosphatase catalyze phosphate liberation from ATP and ADP, as well as from pyrophosphate, in the presence of zinc ions.2. 2. A variety of other nucleoside di- and triphosphates are hydrolyzed in the presence of zinc ions and pyrophosphatase, and manganous and cobaltous ions can partially substitute for zinc in effecting ATP hydrolysis.3. 3. Although several lines of evidence suggest that a single protein possesses Mg++-pyrophosphatase and Zn++-ATPase activities, the possibility cannot be eliminated that a different protein, present in small amounts, accounts for the ATPase activity.4. 4. Evidence has been obtained that the hydrolysis of ATP occurs primarily between the [beta]- and [gamma]-phosphate groups to yield ADP, which is then converted to AMP.