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Retinyl palmitate, or vitamin A palmitate, is the ester of retinol and palmitic acid, with formula C 36 H 60 O 2. It is the most abundant form of vitamin A storage in animals. [2] An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen. [citation needed]
The enzyme 11-cis-retinyl-palmitate hydrolase (EC 3.1.1.63) catalyzes the reaction 11-cis-retinyl palmitate + H 2 O 11-cis-retinol + palmitate. This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name is 11-cis-retinyl-palmitate acylhydrolase.
The primary dietary form is retinol, which may have a fatty acid molecule attached, creating a retinyl ester, when stored in the liver. Retinol – the transport and storage form of vitamin A – is interconvertible with retinal, catalyzed to retinal by retinol dehydrogenases and back to retinol by retinaldehyde reductases.
Retinoic acid (simplified nomenclature for all-trans-retinoic acid) is a metabolite of vitamin A 1 (all-trans-retinol) that is required for embryonic development, male fertility, regulation of bone growth and immune function. [2]
an all-trans-retinyl ester + H 2 O = 11-cis-retinol + a fatty acid. This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name is all-trans-retinyl ester acylhydrolase, 11-cis retinol-forming. This enzyme participates in retinol metabolism.
Retinyl esters can be distinguished from retinol in serum and other tissues and quantified with the use of methods such as high-performance liquid chromatography. [21] Elevated amounts of retinyl ester (i.e., >10% of total circulating vitamin A) in the fasting state have been used as markers for chronic hypervitaminosis A in humans and monkeys ...
Retinol, also called vitamin A 1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. [3] Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. [3]
The major source of retinoids in human diet are plant pigments such as carotenes and retinyl esters derived from animal sources. [15] Retinyl esters are transported through the chylomicron pathway to the liver or fat tissue while retinol or carotenes are transported from the enterocytes to the liver and are processed into retinyl esters by LRAT ...