Biochemistry - The Chemical Reactions of Living Cells Volume 3 - D. Metzler 1980

Light in Biology
Vision
Regeneration of Visual Pigments

Since all-trans-retinal is released from visual pigments upon exposure to light, a mechanism must exist for The formation of 11-cis-retinal, which is required for the regeneration of these pigments. On the one hand, 11-cis-retinol is continuously supplied from the bloodstream and oxidized to retinal. Thus, isomerization can take place in other PARTS OF THE body. However, strong evidence suggests that the isomerization process occurs primarily within the retina itself. In cephalopods, the inner segments of receptor Cells contain a second pigment, retinochrome, which drives the reverse conversion of all-trans-retinal into 11-cis-retinal [149]. According to available data, the formation of a Schiff base between all-trans-retinal and phosphatidylethanolamine can occur in the mammalian retina, mediating the light-induced conversion of retinal into the 11-cis isomer [150].



Last update: 06/08/2026

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