Modulation of retinal transducin and phosphodiesterase activities by synthetic peptides of the phosphodiesterase γ-subunit

AbstractSynthetic peptides corresponding to various regions of the light-activated guanosine 3′,5′-cyclic monophosphate phosphodiesterase (PDE) γ-subunit (PDEγ) from bovine retinal rod outer segments were synthesized and tested for their ability to inhibit PDE activity, and GTPase activity of transducin. One of these peptides, corresponding to PDEγ residues 31–45, inhibited PDE activity and GTPase activity in a dose-dependent manner. The GTPase activity was inhibited by PDEγ-3 non-competitively. This region of the PDEγ subunit may be involved in the direct interaction of transducin and PDEαβ with PDEγ