Thermal recovery of iodopsin from its meta I-intermediate.
The thermal reaction of meta I-intermediate of iodopsin (metaiodopsin I), a chicken red-sensitive cone pigment, was studied by low-temperature spectrophotometry at -20 degrees C. Irradiation of iodopsin at -20 degrees C produced metaiodopsin I, whose absorption maximum was at about 470 nm. An incubation of metaiodopsin I at -20 degrees C resulted in a conversion to metaiodopsin II having absorption maximum at about 380 nm, as well as a concurrent formation of a red-shifted product stable at room temperature. Since the absorption spectrum and photo-reactivity of the red-shifted product were identical with those of iodopsin, the red-shifted product should be iodopsin. Thus a part of metaiodopsin I can revert to iodopsin by the thermal reaction unlike metarhodopsin I.
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Y
Y
Imamoto
H
H
Imai
T
T
Yoshizawa
Y
Y
Shichida
D000818:Animals; D002645:Chickens; D003080:Cold Temperature; D006358:Hot Temperature; D008027:Light; D010777:Photochemistry; D012160:Retina / Q000737:chemistry; D012168:Retinal Pigments / Q000737:chemistry*; D017299:Rod Opsins; D013053:Spectrophotometry
D012168:Retinal Pigments; D017299:Rod Opsins; C034941:iodopsin