[Phosphohydrolases of the phytopathogenic fungus Phytophthora infestans (Mont) de Bary]

ATPase, pyrophosphatase and tripolyhosphatase activities were found in a cell-free Phytophtora infestans micelium extract. No polyphosphatase activity, hydrolyzing high molecular weigh polyphosphates to orthophosphate, was observed in the fungi. It was demonstrated that, unlike ATPase, the activity of pyrophosphatase was inhibited by Ca2+ at concentrations from 0.1 to 20 mM, and it was considerably decreased in the presence of a Ca2+ transport inhibitor, ruthenium red (0.01--0.1 mM). Possible relation of Ph. infestans pyrophosphatase activity with the process of active calcium transport is suggested.