The photoconversion of lumirhodopsin at 77 degrees K. Estimation of the quantum efficiency.
Evidence is presented that lumirhodopsin (containing all-trans retinal) is not directly photoconverted to bathorhodopsin (all-trans) at 77 degrees K as previously suggested (Yoshizawa and Wald. 1963. Nature (Lond.) 197:1279-1286). Rather, lumirhodopsin is converted to a new species, L' (11-cis and/or 9-cis retinal) which, on warming to room temperature, is indistinguishable from rhodopsin or isorhodopsin. The quantum efficiency for the conversion of lumirhodopsin to L' is estimated to be 0.5 +/- 0.1. This value is significantly higher than that of other all-trans to cis conversions for bovine rhodopsin intermediates, indicating that the opsin conformation has a significant effect on a pigment's quantum efficiency.
D000818:Animals; D002417:Cattle; D005615:Freezing; D008433:Mathematics; D010777:Photochemistry; D011789:Quantum Theory; D012168:Retinal Pigments / Q000378:metabolism*; D012243:Rhodopsin / Q000031:analogs & derivatives / Q000378:metabolism*; D012374:Rod Cell Outer Segment; D013053:Spectrophotometry
D012168:Retinal Pigments; C018586:lumirhodopsin; D012243:Rhodopsin