Activation of phosphodiesterase in frog rod outer segment by an intermediate of rhodopsin photolysis. II.
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.
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*
D012168:Retinal Pigments; D012243:Rhodopsin; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D012172:Retinaldehyde