Adenosine phosphate hydrolases in cell fractions of Vitreoscilla.

Bound, soluble, and whole-cell fractions of two strains of the gliding bacterium Vitreoscilla were found to contain two enzymes capable of hydrolyzing adenosine phosphates: a Mg(++)-activated adenosine triphosphatase with a temperature optimum of 37 C, and a Mg(++)-activated adenosine diphosphatase with a temperature optimum of 55 C. Both enzymes had an optimal pH response between 8.5 and 9.5. Maximal activation was achieved at an ionic strength of 0.2 for the adenosine triphosphatase and at 0.3 to 0.4 for the adenosine diphosphatase. Preliminary studies indicated a molecular weight of approximately 50,000 for the adenosine diphosphatase and a molecular weight greater than 60,000 for the adenosine triphosphatase. Comparisons are made with previously reported characteristics of these enzymes in other bacteria, and a hypothesis is offered as to the role these enzymes have in the gliding mechanism.