Abstract
An enzyme that hydrolyzes cyclic ',5'-adenosine monophosphate to 5'-adenosine monophosphate was found in the culture medium of the cellular slime mold Dictyostelium discoidum. The enzymatic activity shows a pH optimum of 7.5, and magnesium is required for maximum activity. The enzyme is not inhibited by caffeine. It has a Michaelis-Menten constant of 2 x 10-3M and its molecular weight is around 300,000.