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* Jin M, Li S, Moghrabi WN, Sun H, Travis GH. ''Rpe65 is the retinoid isomerase in bovine retinal pigment epithelium.'' Cell. 2005 [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed Article].
 
* Jin M, Li S, Moghrabi WN, Sun H, Travis GH. ''Rpe65 is the retinoid isomerase in bovine retinal pigment epithelium.'' Cell. 2005 [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed Article].
   
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[[Category:Vision]]
 
[[Category:Vision]]
 
[[Category:Sensory receptors]]
 
[[Category:Sensory receptors]]

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It has been suggested that this article or section be merged into [[::Visual phototransduction|Visual phototransduction]]. (Discuss)

The Visual Cycle

The visual cycle refers to the conversion of a photon into an action potential in the retina. This process occurs via G-protein coupled receptors called opsins which contain the chromophore 11-cis retinal. 11-cis retinal is covalently linked to the opsin receptor via a schiff base forming a retinylidene protein. When struck by a photon, 11-cis retinal undergoes photoisomerization to all-trans retinal which changes the conformation of the opsin GPCR leading to signal transduction cascades which ultimately causes an action potential which results in visual perception.

Following isomerization and release from the opsin protein, all-trans retinal is reduced to all-trans retinol and travels back to the retinal pigment epithelium to be "recharged". It is first esterified by lecithin-retinol acyltransferase (LRAT) and then converted to 11-cis retinol by the isomerohydrolase RPE65. Finally, it is oxidized to 11-cis retinal before traveling back to the rod outer segment where it can again be conjugated to an opsin to form a new, functional visual pigment (rhodopsin).

References

  • Moiseyev G, Chen Y, Takahashi Y, Wu BX, Ma JX. RPE65 is the isomerohydrolase in the retinoid visual cycle. Proc. Nat. Acad. Sci. 2005 Article.
  • Jin M, Li S, Moghrabi WN, Sun H, Travis GH. Rpe65 is the retinoid isomerase in bovine retinal pigment epithelium. Cell. 2005 Article.

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Glucuronate metabolism
Pentose interconversion
Inositol metabolism
Cellulose and sucrose
metabolism
Starch and glycogen
metabolism
Other sugar
metabolism
Amino sugars metabolism
Small amino acid synthesis
Branched amino acid
synthesis
Purine biosynthesis
Histidine metabolism
Aromatic amino
acid synthesis
Anaerobic
respiration
Aspartate amino acid
group synthesis
Porphyrins and
corrinoids
metabolism
Glutamate amino
acid group
synthesis
Pyrimidine biosynthesis
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