Reactome: A Curated Pathway Database

The canonical retinoid cycle in rods (twilight vision) (R-HSA-2453902)

Species Homo sapiens


The retinoid cycle (also referred to as the visual cycle) is the process by which the visual chromophore 11-cis-retinal (11cRAL) is released from light-activated opsins in the form all-trans-retinal and isomerized back to its 11-cis isomer ready for another photoisomerization reaction. This process involves oxidation, reduction and isomerization reactions and take place in the retinal pigment epithelium (RPE) and photoreceptor segments of the eye (von Lintig 2012, Blomhoff & Blomhoff 2006, von Lintig et al. 2010, D'Ambrosio et al. 2011). This section describes the retinoid cycle in rods during dark/twilight conditions.

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Additional Information
GO Biological Process retinoid metabolic process (0001523)
Literature References
pubMedId Title Journal Year
22074927 Metabolism of carotenoids and retinoids related to vision J. Biol. Chem. 2012
16688755 Overview of retinoid metabolism and function J. Neurobiol. 2006
20188572 The biochemical and structural basis for trans-to-cis isomerization of retinoids in the chemistry of vision Trends Biochem. Sci. 2010
21350678 Vitamin A metabolism: an update Nutrients 2011