title: Inhibition of rhodopsin regeneration by cyclohexyl derivatives.
abstract: Twenty two compounds, bearing some structural similarity either to the ring-end or aldehyde-end of 11-cis-retinal, have been screened for their effectiveness in decreasing the rate of regeneration of rhodopsin in vitro from 11-cis retinal and bovine opsin. The results of these experiments indicate that only those compounds containing a ring and having at least two methyl groups at the 1,5-ring positions are capable of decreasing the rate of regeneration of rhodopsin. Short-chain aldehydes resembling the aldehyde-end of retinal did not affect the rate of pigment formation. There was no additive effect of combining a dimethylcyclohexyl inhibitor and a short chain aldehyde. The methyl groups at the 1,5-positions may play a special role in anchoring the retinal into the protein binding site. This hypothesis is supported by the failure of the ring demethylated analogue, 11-cis, 1,1,5-desmethyl-5,6-dihydroretinal, to form pigment under the same conditions with which good pigment yields are obtained with 11-cis 5,6-dihydroretinal.
mesh_terms: D001665:Binding Sites; D005136:Eye Proteins; D007700:Kinetics; D012168:Retinal Pigments / Q000037:antagonists & inhibitors*; D012172:Retinaldehyde / Q000031:analogs & derivatives* / Q000494:pharmacology; D012243:Rhodopsin / Q000037:antagonists & inhibitors*; D017299:Rod Opsins; D013053:Spectrophotometry; D013329:Structure-Activity Relationship; D014801:Vitamin A / Q000031:analogs & derivatives*
chemical_list: D005136:Eye Proteins; D012168:Retinal Pigments; D017299:Rod Opsins; D014801:Vitamin A; D012243:Rhodopsin; D012172:Retinaldehyde