Enzyme activity and bacteriophage infection. I. Breakdown of adenosinetriphosphate.

Experiments have been performed on the apyrase activity of E. coli, strain B. Although the dependence on pH and substrate is similar to that of rat tissue, the bacterial extracts are inhibited by Ca(++) and stimulated by Mg(++). In bacterial extracts the rate of phosphate release decreases in the course of the reaction, possibly owing to product inhibition. With multiple bacteriophage infection, the apyrase activity of the intact cells increased several fold, and the activity of extracts increased about 30 per cent. It is suggested that the changes could be attributed to an increase in the amount of enzyme although other alternatives cannot be precluded at present.