retinal

1. Relating to the retina. 2. Retinaldehyde; most commonly referring to the all-trans form.

- r. dehydrogenase an oxidoreductase catalyzing the interconversion of retinaldehyde and NAD⁺ to retinoic acid and NADH, thus affecting growth and differentiation. SYN: retinaldehyde dehydrogenase.

- r. isomerase an isomerase that catalyzes the cis-trans-interconversion of all-trans-r. to 11-cis-r.(dehyde); a part of the vision cycle. SYN: retinaldehyde isomerase.

- r. reductase alcohol dehydrogenase (NAD(P)⁺).

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ret·i·nal 'ret-ən-əl, 'ret-nəl adj of, relating to, involving, or being a retina <a \retinal examination> <\retinal rods>

ret·i·nal 'ret-ən-.al, -.ȯl n a yellowish to orange aldehyde C₂₀H₂₈O derived from vitamin A that in combination with proteins forms the visual pigments of the retinal rods and cones called also retinene, retinene₁, vitamin A aldehyde

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n.

the aldehyde of retinol (vitamin A). See also rhodopsin.

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ret·i·nal (retґĭ-nəl) 1. pertaining to the retina. 2. the aldehyde of retinol, derived from absorbed dietary carotenoids or esters of retinol and having vitamin A activity. In the retina, retinal combines with opsins of rods (scotopsins) and cones (photopsins), functioning as the prosthetic group in the resulting visual pigments rhodopsin and the iodopsins.