Hydrolyzes cAMP to 5'-AMP and cGMP to 5'-GMP. Does not show phosphohydrolase activity toward various phosphatidylcholine and phosphorylated sugars. a nucleoside 3',5'-cyclic phosphate + H2O = a nucleoside 5'-phosphate + H(+) kcat is 2008 min(-1) and 957 min(-1) with cAMP and cGMP as substrate, respectively. Optimum pH is 4.0-4.5. Optimum temperature is 30-40 degrees Celsius.