Phytoene is a 40-carbon intermediate in the biosynthesis of carotenoids. The synthesis of phytoene is the first committed step in the synthesis of carotenoids in plants. Phytoene is produced from two molecules of geranylgeranyl pyrophosphate (GGPP) by the action of the enzyme phytoene synthase. The two GGPP molecules are condensed together followed by removal of diphosphate and proton shift leading to the formation of phytoene. Dietary phytoene and phytofluene are accumulated in human skin. The accumulation of these carotenoids may protect the skin by several mechanisms: acting as UV absorbers, as antioxidants, and as anti-inflammatory agents. Phytoene is a symmetric molecule containing three conjugated double bonds. Analysis of several fruits and vegetables showed that phytoene and phytofluene are found in majority of fruits and vegetables.
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