Which of the following enzymes is activated by Transducin during phototransduction?

During phototransduction, the visual signal is processed in the photoreceptor cells of the retina when light is absorbed by photopigments. This process is initiated when a photon of light activates rhodopsin, the pigment found in rods. When rhodopsin is activated, it undergoes a conformational change and activates a G-protein called transducin.

Transducin, upon activation, interacts with phosphodiesterase (PDE 6), which is the specific enzyme responsible for the hydrolysis of cyclic guanosine monophosphate (cGMP). The activation of PDE 6 leads to a decrease in cGMP levels in the photoreceptor cell. As cGMP levels drop, the cGMP-gated ion channels close, resulting in hyperpolarization of the photoreceptor cell and the initiation of the visual signal sent to the bipolar and ganglion cells in the retina.

This sequence highlights the crucial role of PDE 6 in the phototransduction cascade. It is important to understand that transducin does not activate Rho kinase, adenylyl cyclase, or guanylate cyclase in this context. Instead, its primary action is to activate PDE 6,