Reaction participants Show >> << Hide
- Name help_outline an all-trans-retinyl ester Identifier CHEBI:63410 Charge 0 Formula C21H29O2R SMILEShelp_outline CC(\C=C\C=C(C)\C=C\C1=C(C)CCCC1(C)C)=C/COC([*])=O 2D coordinates Mol file for the small molecule Search links Involved in 19 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,204 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 13-cis-retinol Identifier CHEBI:45479 (Beilstein: 1913943; CAS: 2052-63-3) help_outline Charge 0 Formula C20H30O InChIKeyhelp_outline FPIPGXGPPPQFEQ-HWCYFHEPSA-N SMILEShelp_outline CC(\C=C\C=C(C)\C=C\C1=C(C)CCCC1(C)C)=C\CO 2D coordinates Mol file for the small molecule Search links Involved in 8 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline a fatty acid Identifier CHEBI:28868 Charge -1 Formula CO2R SMILEShelp_outline [O-]C([*])=O 2D coordinates Mol file for the small molecule Search links Involved in 1,526 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:31779 | RHEA:31780 | RHEA:31781 | RHEA:31782 | |
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More general form(s) of this reaction
Publications
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An enzymatic mechanism for generating the precursor of endogenous 13-cis retinoic acid in the brain.
Takahashi Y., Moiseyev G., Chen Y., Farjo K., Nikolaeva O., Ma J.X.
13-cis Retinoic acid (13cRA), a stereoisomeric form of retinoic acid, is naturally generated in the body and is also used clinically to treat acute promyelocytic leukemia, some skin diseases and cancer. Furthermore, it has been suggested that 13cRA modulates brain neurochemical systems because inc ... >> More
13-cis Retinoic acid (13cRA), a stereoisomeric form of retinoic acid, is naturally generated in the body and is also used clinically to treat acute promyelocytic leukemia, some skin diseases and cancer. Furthermore, it has been suggested that 13cRA modulates brain neurochemical systems because increased 13cRA levels are correlated with depression and increased suicidal tendencies. However, the mechanism for the generation of endogenous 13cRA is not well understood. The present study identified and characterized a novel enzyme in zebrafish brain, 13-cis isomerohydrolase (13cIMH) (EC 5.2.1.7), which exclusively generated 13-cis retinol and can be oxidized to 13cRA. 13cIMH shares 74% amino acid sequence identity with human retinal pigment epithelium specific 65 kDa protein (RPE65), an 11-cis isomerohydrolase in the visual cycle, and retains the key residues essential for the isomerohydrolase activity of RPE65. Similar to RPE65, 13cIMH is a membrane-associated protein, requires all-trans retinyl ester as its intrinsic substrate, and its enzymatic activity is dependent on iron. The purified 13cIMH converted all-trans retinyl ester exclusively to 13-cis retinol with K(m) = 2.6 μm and k(cat) = 4.4 × 10(-4) ·s(-1) . RT-PCR, western blot analysis and immunohistochemistry detected 13cIMH expression in the brain. These results suggest that 13cIMH may play a key role in the generation of 13cRA, as well as in the modulation of neuronal functions in the brain. << Less
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An alternative isomerohydrolase in the retinal Muller cells of a cone-dominant species.
Takahashi Y., Moiseyev G., Chen Y., Nikolaeva O., Ma J.X.
Cone photoreceptors have faster light responses than rods and a higher demand for 11-cis retinal (11cRAL), the chromophore of visual pigments. RPE65 is the isomerohydrolase in the retinal pigment epithelium (RPE) that converts all-trans retinyl ester to 11-cis retinol, a key step in the visual cyc ... >> More
Cone photoreceptors have faster light responses than rods and a higher demand for 11-cis retinal (11cRAL), the chromophore of visual pigments. RPE65 is the isomerohydrolase in the retinal pigment epithelium (RPE) that converts all-trans retinyl ester to 11-cis retinol, a key step in the visual cycle for regenerating 11cRAL. Accumulating evidence suggests that cone-dominant species express an alternative isomerase, likely in retinal Müller cells, to meet the high demand for the chromophore by cones. In the present study, we describe the identification and characterization of a novel isomerohydrolase, RPE65c, from the cone-dominant zebrafish retina. RPE65c shares 78% amino acid sequence identity with RPE-specific zebrafish RPE65a (orthologue of human RPE65) and retains all of the known key residues for the enzymatic activity of RPE65. Similar to the other RPE-specific RPE65, RPE65c was present in both the membrane and cytosolic fractions, used all-trans retinyl ester as its substrate and required iron for its enzymatic activity. However, immunohistochemistry detected RPE65c in the inner retina, including Müller cells, but not in the RPE. Furthermore, double-immunostaining of dissociated retinal cells using antibodies for RPE65c and glutamine synthetase (a Müller cell marker), showed that RPE65c co-localized with the Müller cell marker. These results suggest that RPE65c is the alternative isomerohydrolase in the intra-retinal visual cycle, providing 11cRAL to cone photoreceptors in cone-dominant species. Identification of an alternative visual cycle will contribute to the understanding of the functional differences of rod and cone photoreceptors. << Less
FEBS J. 278:2913-2926(2011) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.