title: Activation of phosphodiesterase in frog rod outer segment by an intermediate of rhodopsin photolysis. II.
abstract: Frog (Rana catesbeiana) rod outer segment membrane contains cyclic GMP phosphodiesterase (EC 3.1.4.1). Irradiation of dark-adapted rod outer segment membrane increased the enzyme activity by 5-20-fold in the presence of GTP. The phosphodiesterase in rod outer segment membrane is also activated by mixing a photo-product of 11-cis (regenerated), 9-cis or 7-cis rhodopsin which is stable at 0 degrees C. However, neither opsin in the membrane nor all-trans retinal activates the enzyme. The phosphodiesterase in rod outer segment membrane is also activated by irradiation at -4 degrees C. Thus, we conclude that the phosphodiesterase in activated by a common photolysis intermediate of these rhodopsin isomers, perhaps before metarhodopsin II decays.
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism* / Q000528:radiation effects; D000818:Animals; D004789:Enzyme Activation; D005615:Freezing; D010782:Photolysis; D010786:Photoreceptor Cells / Q000201:enzymology*; D011892:Rana catesbeiana / Q000378:metabolism*; D012168:Retinal Pigments / Q000494:pharmacology*; D012172:Retinaldehyde / Q000494:pharmacology; D012243:Rhodopsin / Q000494:pharmacology* / Q000528:radiation effects; D012374:Rod Cell Outer Segment / Q000201:enzymology*
chemical_list: D012168:Retinal Pigments; D012243:Rhodopsin; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D012172:Retinaldehyde