Lecithin retinol acyltransferase; Transfers the acyl group from the sn-1 position of phosphatidylcholine to all-trans retinol, producing all-trans retinyl esters (By similarity). Retinyl esters are storage forms of vitamin A (By similarity). LRAT plays a critical role in vision (By similarity). It provides the all-trans retinyl ester substrates for the isomerohydrolase which processes the esters into 11-cis-retinol in the retinal pigment epithelium; due to a membrane-associated alcohol dehydrogenase, 11 cis-retinol is oxidized and converted into 11-cis- retinaldehyde which is the chrom [...]

Retinoid isomerohydrolase; Critical isomerohydrolase in the retinoid cycle involved in regeneration of 11-cis-retinal, the chromophore of rod and cone opsins. Catalyzes the cleavage and isomerization of all-trans-retinyl fatty acid esters to 11-cis-retinol which is further oxidized by 11-cis retinol dehydrogenase to 11-cis-retinal for use as visual chromophore. Essential for the production of 11-cis retinal for both rod and cone photoreceptors. Also capable of catalyzing the isomerization of lutein to meso-zeaxanthin an eye-specific carotenoid. The soluble form binds vitamin A (all-tra [...]

Retinol dehydrogenase 5; Catalyzes the oxidation of cis-isomers of retinol, including 11-cis-, 9-cis-, and 13-cis-retinol in an NAD-dependent manner. Has no activity towards all-trans retinal (By similarity). Plays a significant role in 11-cis retinol oxidation in the retinal pigment epithelium cells (RPE). Also recognizes steroids (androsterone, androstanediol) as its substrates (By similarity). ECO:0000250|UniProtKB:Q92781, ; Belongs to the short-chain dehydrogenases/reductases (SDR) family.

Aldehyde dehydrogenase family 1 member A3; NAD-dependent aldehyde dehydrogenase that catalyzes the formation of retinoic acid. Has high activity with all-trans retinal, and has much lower in vitro activity with acetaldehyde (By similarity). Required for the biosynthesis of normal levels of retinoic acid in the embryonic ocular and nasal regions; retinoic acid is required for normal embryonic development of the eye and the nasal region.

Beta,beta-carotene 15,15'-dioxygenase; Symmetrically cleaves beta-carotene into two molecules of retinal using a dioxygenase mechanism; Belongs to the carotenoid oxygenase family.

Cytochrome P450 26A1; A cytochrome P450 monooxygenase involved in the metabolism of all-trans retinoic acid (atRA), a signaling molecule that binds to retinoic acid receptors and regulates gene transcription. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH- ferrihemoprotein reductase). Catalyzes the hydroxylation of carbon hydrogen bonds of atRA primarily at C-4 and C-18. Has no activity toward 9-cis and 13-cis retinoic acid st [...]

Retinal dehydrogenase 1; Can convert/oxidize retinaldehyde to retinoic acid. Binds free retinal and cellular retinol-binding protein-bound retinal (By similarity). May have a broader specificity and oxidize other aldehydes in vivo (By similarity).

Retinal dehydrogenase 2; Converts retinaldehyde to retinoic acid. Recognizes as substrates free retinal and cellular retinol-binding protein-bound retinal (By similarity). Lacks activity with benzaldehyde, acetaldehyde and octanal. Displays complete lack of activity with citral (By similarity).

All-trans-retinol 13,14-reductase; Catalyzes the saturation of all-trans-retinol to all-trans- 13,14-dihydroretinol. Does not exhibit any activity toward all-trans- retinoic acid, nor 9-cis, 11-cis or 13-cis-retinol isomers. May play a role in the metabolism of vitamin A. Independently of retinol conversion, may regulate liver metabolism upstream of MLXIPL/ChREBP. Required for adipocyte differentiation in a 3T3-L1 cell culture model. This effect seems not to mimic the in vivo situation in which animals show increased adiposity in the absence of RETSAT. Belongs to the carotenoid/retinoi [...]