A separate phosphodiesterase for the hydrolysis of cyclic guanosine 3',5'-monophosphate in growing Dictyostelium discoideum amoebae.

The presence of a cyclic guanosine 3',5'-monophosphate (cGMP) phosphodiesterase in mutant Dictyostelium discoideum amoebae, deficient in cyclic adenosine 3',5'-monophosphate (cAMP) phosphodiesterase is demonstrated. This enzyme shows a high affinity for cGMP and is not affected by cAMP at concentrations of up to 0.3 mM. It is activated by Mg2+ and Mn2+, and displays no apparent heterogeneity. Biochemical analysis of wild-type amoebae revealed the presence of a cGMP-specific phosphodiesterase sharing several common characteristics with the enzyme of the mutant amoebae. From the evidence presented in this report, it is concluded that the cGMP and cAMP phosphodiesterases of D. discoideum are under separate genetic control.