Retinol is one of the animal forms of vitamin A. It is a diterpenoid and an alcohol. It is convertible to other forms of vitamin A, and the retinyl ester derivative of the alcohol serves as the storage form of the vitamin in animals.

When converted to the retinal (retinaldehyde) form, vitamin A is essential for vision, and when converted to retinoic acid, is essential for skin health, teeth remineralization and bone growth. These chemical compounds are collectively known as retinoids, and possess the structural motif of all-trans retinol as a common feature in their structure. Structurally, all retinoids also possess a β-ionone ring and a polyunsaturated side chain, with either an alcohol, aldehyde, a carboxylic acid group or an ester group. The side chain is composed of four isoprenoid units, with a series of conjugated double bonds which may exist in trans- or cis-configuration.

Retinol is produced in the body from the hydrolysis of retinyl esters, and from the reduction of retinal. Retinol in turn is ingested in a precursor form; animal sources (liver and eggs) contain retinyl esters, whereas plants (carrots, spinach) contain pro-vitamin A carotenoids (these may also be considered simply vitamin A). Hydrolysis of retinyl esters results in retinol, while pro-vitamin A carotenoids can be cleaved to produce retinal by carotene dioxygenase in the intestinal mucosa. Retinal, also known as retinaldehyde, can be reversibly reduced to produce retinol or it can be irreversibly oxidized to produce retinoic acid, which then cannot function as the vitamin in the eye.

Commercial production of retinol typically requires retinal synthesis through reduction of a pentadiene derivative and subsequent acidification/hydrolysis of the resulting isomer to produce retinol. Pure retinol is extremely sensitive to oxidization and is prepared and transported at low temperatures and oxygen free atmospheres. When prepared as a dietary supplement, retinol is stabilized as the ester derivatives retinyl acetate or retinyl palmitate.

Read more about Retinol:  Discovery, Chemical Structure and Function, Biosynthesis of Retinol, Clinical Use, Units of Measurement, Nutrition, Closely Related Chemicals, Genetically Engineered Vitamin A Enriched Rice

Other articles related to "retinol":

All-trans-retinyl-palmitate Hydrolase
... that catalyzes the chemical reaction all-trans-retinyl palmitate + H2O all-trans-retinol + palmitate Thus, the two substrates of this enzyme are all-trans-retinyl palmitate and H2O ... This enzyme participates in retinol metabolism ...
TROL - Equivalencies of Retinoids and Carotenoids (IU)
... them in the diet is equivalent to a particular amount of retinol, so that comparisons can be made of the benefit of different foods ... a system of equivalencies in which an international unit (IU) was equal to 0.3 μg of retinol, 0.6 μg of β-carotene, or 1.2 μg of other provitamin-A carotenoids was used ... Later, a unit called retinol equivalent (RE) was introduced ...
All-trans-retinol 13,14-reductase
... In enzymology, an all-trans-retinol 13,14-reductase (EC is an enzyme that catalyzes the chemical reaction all-trans-13,14-dihydroretinol + acceptor all-trans-retinol + reduced acceptor Thus, the ... the opposite direction catalyzing the saturation of the 13-14 double bond of all-trans-retinol ... Other names in common use include retinol saturase, RetSat, (13,14)-all-trans-retinol saturase, and all-trans-retinolall-trans-13,14-dihydroretinol saturase ...
Lipocalin - Function - Retinoid Binding
... Retinol, (vitamin A), is an important micronutrient that affects eyesight, cell differentiation, immune system function, bone growth, and tumor suppression ... Retinol absorption and metabolism depends on lipocalins that act as binding proteins ... After intake, they are converted to retinol, successively metabolized, and finally bound to retinol binding proteins (lipocalins) in the blood plasma ...
Phosphatidylcholine-retinol O-acyltransferase
... In enzymology, a phosphatidylcholine---retinol O-acyltransferase (EC is an enzyme that catalyzes the chemical reaction phosphatidylcholine + retinol--- 2-acylglycerophosphocholine ...