The role of vitamin A in the visual cycle is specifically related to the retinal form.

It modulates interaction of retinoids with visual cycle enzymes.

The visual cycle is the biological conversion of photon into an electrical signal in the retina.

RPE65 is the isomerohydrolase in the retinoid visual cycle.

This suggests that RDH12 might play a central role in the visual cycle and can be a promising therapeutic target.

In a normal, healthy retina, this protein acts as an isomerase, converting all-trans-retinol to 11-cis-retinol in the visual cycle.

Under normal conditions when light hits a photoreceptor, the cell bleaches and becomes useless until it has recovered through a metabolic process called the visual cycle.

RDH12 is the primary enzyme that reduces all-trans retinal released from bleached photopigments during recovery phase in the visual cycle.

The latter is a storage form of Vitamin A in various tissues, as well as a visual pigment precursor in the retina (see visual cycle).

The regeneration of 11-cis-retinal occurs in vertebrates via a sequence of chemical transformations that constitute "the visual cycle" and which occurs primarily in the retinal pigmented epithelial cells.

The associated acid (retinoic acid), a metabolite that can be irreversibly synthesized from vitamin A, has only partial vitamin A activity, and does not function in the retina for the visual cycle.

Biotinylated retinoids are derivatives of retinol (vitamin A) carrying a biotin group for use in the isolation and purification of Retinol Binding Proteins involved in the visual cycle.

Retinene is better known as retinaldehyde or simply retinal and is fundamental in the transduction of light into visual signals in the photoreceptor level of the retina (known as the visual cycle).

Retinoid dehydrogenases/reductases (oxidoreductases), including retinol dehydrogenase, catalyze the key oxidation-reduction reactions in the visual cycle, converting vitamin A to 11-cis retinal, which is the chromophore of the rod and cone photoreceptors.

John Dowling, Ph.D., received the award in 2001 for his groundbreaking work in understanding the functional organization of the retina, including synaptic organization, electrical responses of retinal neurons, and the exchange of retinoids in the visual cycle.

All have produced epic visual cycles on the phenomenon, but their appearance together in the show "Disasters of War: Francisco de Goya, Henry Darger, Jake and Dinos Chapman" at P.S. 1 could be regarded as either a brilliant stretch or a curatorial overreach.

However, not all retinol dehydrogenases in visual cycle are identified, and this remains challenging to scientists due to the overlapping expressions and activity redundancy among two large RDH and RDH-like producing classes: microsomal short-chain dehydrogenase/reductase and cytosolic medium-chain alcohol dehydrogenases.