Bibliographic Citation
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Title | Photochemistry and stereoselectivity of cellular retinaldehyde-binding protein from bovine retina |
Creator/Author | Saari, J.C. ; Bredberg, D.L. |
Publication Date | 1987 Jun 05 |
OSTI Identifier | OSTI ID: 6280353 |
Other Number(s) | CODEN: JBCHA |
Resource Type | Journal Article |
Resource Relation | J. Biol. Chem. ; Vol/Issue: 16 |
Research Org | Univ. of Washington School of Medicine, Seattle |
Subject | 550201 -- Biochemistry-- Tracer Techniques; ALDEHYDES-- BIOCHEMICAL REACTION KINETICS;RHODOPSIN-- BIOCHEMICAL REACTION KINETICS;RHODOPSIN-- PHOTOCHEMISTRY; CATTLE;RETINA;RETINOIC ACID;SPECTROPHOTOMETRY;TRACER TECHNIQUES;TRITIUM COMPOUNDS |
Related Subject | ANIMALS;BODY;BODY AREAS;CARBOXYLIC ACID ESTERS;CHEMISTRY;DOMESTIC ANIMALS;ESTERS;EYES;FACE;HEAD;ISOTOPE APPLICATIONS;KINETICS;LABELLED COMPOUNDS;MAMMALS;ORGANIC COMPOUNDS;ORGANS;PIGMENTS;PROTEINS;REACTION KINETICS;RUMINANTS;SENSE ORGANS;VERTEBRATES |
Description/Abstract | 11-cis-Retinaldehyde bound to cellular retinaldehyde-binding protein (CRALBP) is unaffected in bovine eyecup preparations by illumination that bleaches approximately 70% of the rhodopsin.^Illumination of retinal homogenates to which CRALBP X (/sup 3/H)11-cis-retinaldehyde had been added did not result in a reduction of the specific activity of recovered 11-cis-retinaldehyde, ruling out a bleaching regeneration cycle.^The quantum efficiency of photoisomerization for CRALBP X 11-cis-retinaldehyde was determined by comparing the rate of photoisomerization of 11-cis-retinaldehyde bound to purified CRALBP and opsin.^The low value obtained (0.07), coupled with a low molar extinction coefficient (15,400 M-1 cm-1), results in a photosensitivity only about 4% that of rhodopsin.^CRALBP binds 9-cis- and 11-cis-retinaldehyde, producing complexes with absorption maxima at 405 and 425 nm, respectively.^No complexes were detected with 13-cis- and all-trans-retinaldehyde.^Following incubation of CRALBP X 11-cis-retinol with an equimolar mixture of 9-, 11-, 13-cis-, and all-trans-retinaldehydes, only 11-cis-retinaldehyde and residual 11-cis-retinol are present on the protein following separation from excess retinoids.^A similar result is obtained following incubation of CRALBP X 11-cis-retinol with mixtures of 9- and 11-cis-retinaldehyde ranging in composition from 9:1 to 1:9 (9-cis-:11-cis-,mol/mol).^The results indicate that CRALBP X 11-cis-retinol is sufficiently stereoselective in its binding properties to warrant consideration as a component of the mechanism for the generation of 11-cis-retinaldehyde in the dark. |
Country of Publication | United States |
Language | English |
Format | Pages: 7618-7622 |
System Entry Date | 2001 May 13 |
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