Phosphodiesterase specific for cGMP, which is not activated by cGMP. Involved in the degradation of intracellular cGMP. 3',5'-cyclic GMP + H2O = GMP + H(+) Binds 2 divalent metal cations per subunit. Site 1 may preferentially bind zinc ions, while site 2 has a preference for magnesium and/or manganese ions. Inhibited by 3-isobutyl-1-methylxanthine (IBMX). cAMP/cGMP selectivity of 0.0015. Expression is constant throughout the development. Composed of a C-terminal catalytic domain containing two putative divalent metal sites and an N-terminal regulatory domain. Shows a moderate phenotype with increased basal cGMP levels, but only a small effect on cAMP-stimulated cGMP levels. Belongs to the cyclic nucleotide phosphodiesterase family.