γ-Carotene is a
carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, cor ...
, and is a biosynthetic intermediate for cyclized carotenoid synthesis in plants. It is formed from cyclization of
lycopene
Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene (from the neo-Latin '' Lycopersicum'', the tomato species) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.
Occ ...
by
lycopene cyclase
Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene (from the neo-Latin '' Lycopersicum'', the tomato species) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.
Occu ...
epsilon.
[Rodriguez-Concepcion M, Stange C. Biosynthesis of carotenoids in carrot: an underground story comes to light. Archives of biochemistry and biophysics. 2013;539:110-6.] Along with several other
carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, cor ...
s, γ-Carotene is a
vitamer
Vitamins occur in a variety of related forms known as vitamers. A vitamer () of a particular vitamin is one of several related compounds that performs the functions of said vitamin and prevents the symptoms of deficiency of said vitamin.
Early r ...
of
vitamin A
Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably ...
in herbivores and omnivores. Carotenoids with a cyclized, beta-ionone ring can be converted to
vitamin A
Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably ...
, also known as
retinol
Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family found in food and used as a dietary supplement. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xerophth ...
, by the
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
Beta-carotene 15,15'-dioxygenase
In enzymology, beta-carotene 15,15'-dioxygenase, () is an enzyme with systematic name ''beta-carotene:oxygen 15,15'-dioxygenase (bond-cleaving)''. In human it is encoded by the BCDO2 gene. This enzyme catalyses the following chemical reaction
...
; however, the bioconversion of gamma-carotene to retinol has not been well-characterized.
References
Carotenoids
Cyclohexenes
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