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Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle.Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji (wolfberries), and many other plants and microbes their characteristic color.
Among eukaryotes, plants and algae inherited the cyanobacterial pathway via biosynthesis of their plastids, while fungi retain a archaeal-like pathway. [4] Among all these synthesizers, several possible selection and arrangements of biosynthetic genes exist, consisting of one gene cluster cluster, several clusters, or no clustering at all.
During light stress, violaxanthin is converted, i.e. reduced, to zeaxanthin via the intermediate antheraxanthin, which plays a direct photoprotective role acting as a lipid-protective anti-oxidant and by stimulating non-photochemical quenching within light-harvesting proteins.
Meso-zeaxanthin (3R,3′S-zeaxanthin) is a xanthophyll carotenoid, and is one of the three stereoisomers of zeaxanthin. The meso- form is the second most abundant in nature, after 3R,3′R-zeaxanthin, which is produced by plants and algae. [ 1 ]
In plants, it is an intermediate in the biosynthesis of the plant hormone abscisic acid. It is often present in two forms: all-trans and 9-cis isomers. It is produced from violaxanthin, but a suspected neoxanthin synthase [1] is still to be confirmed.
Astaxanthin / æ s t ə ˈ z æ n θ ɪ n / is a keto-carotenoid within a group of chemical compounds known as carotenones or terpenes. [3] [4] [5] Astaxanthin is a metabolite of zeaxanthin and canthaxanthin, containing both hydroxyl and ketone functional groups.
Phaseic acid is a product of abscisic acid, which is itself the product of the C 40 carotenoid zeaxanthin via at least four enzymatic steps. Zeaxanthin is epoxidized to form violaxanthin or neoxanthin. The C 15 end of the molecule is then cleaved by an epoxycarotenoid epoxygenase to form xanthoxin, an aldehyde.
Zeaxanthin epoxidase is a flavoprotein (FAD) that is active under conditions of low light. References External links. Zeaxanthin+epoxidase at the U.S. National ...