[Retinal-sensitized photo-oxidation of rhodopsin].
Kinetics of retinal photosensitized initiation of radicals of sulfhydryl groups of cysteine and rhodopsin is investigated by spin trapping. Photooxidation of both systems is the result of free radical mechanism. Photooxidation of SH-groups proceeds both with singlet oxygen participation and by direct interaction of photosensitizer with the substrate. The rate constants of these reactions are measured. The rate constant with oxygen participation (K0 = 1.1 X 10(9) M-1 S-1) is higher than the one without oxygen (K = 2.5 X 10(8) M-1 S-1) correspondingly. The lifetime of retinal triplet state in photoreceptor membrane is tau = 4 X 10(-6) s.
D000818:Animals; D002417:Cattle; D005609:Free Radicals; D066298:In Vitro Techniques; D007700:Kinetics; D010084:Oxidation-Reduction; D010777:Photochemistry; D010786:Photoreceptor Cells / Q000378:metabolism*; D012168:Retinal Pigments / Q000378:metabolism*; D012172:Retinaldehyde / Q000378:metabolism*; D012176:Retinoids / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*; D012374:Rod Cell Outer Segment / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism
D005609:Free Radicals; D012168:Retinal Pigments; D012176:Retinoids; D013438:Sulfhydryl Compounds; D012243:Rhodopsin; D012172:Retinaldehyde
Sensibilizirovannoe retinalem fotookislenie rodopsina.