Interaction of bovine rhodopsin with calcium ions. I: the metarhodopsin I--II reaction and the regeneration of rhodopsin.
The formation of metarhodopsin II in various bovine rhodopsin preparations (rod outer segment (ROS) suspensions and rhodopsin-detergent solutions) was measured by means of flash spectrophotometry. The half-lifetime and formation of metarhodopsin II in ROS did not depend on the calcium concentration in the range of less than 10(-9) M (using EGTA ro EDTA) to 15 x 10(-3) M calcium at pH values of 5.0, 7.1, and 9.0 (Table 1). The regeneration of rhodopsin from opsin by adding 11-cis retinal to ROS-suspensions and rhodopsin digitonin solutions was measured spectrophotometrically. It was not substantially different in either saline, one containing less than 10(-7) M calcium (by adding EGTA), the other containing 10(-3) M calcium (Table 2).
D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D002417:Cattle; D005136:Eye Proteins / Q000378:metabolism; D007700:Kinetics; D008027:Light; D010786:Photoreceptor Cells / Q000502:physiology; D012168:Retinal Pigments / Q000502:physiology*; D012172:Retinaldehyde / Q000378:metabolism; D012243:Rhodopsin / Q000096:biosynthesis / Q000502:physiology* / Q000528:radiation effects; D013053:Spectrophotometry; D013696:Temperature; D013997:Time Factors
D005136:Eye Proteins; D012168:Retinal Pigments; D012243:Rhodopsin; D012172:Retinaldehyde; D002118:Calcium