Skip to main content
. 2018 Dec 18;9:1862. doi: 10.3389/fpls.2018.01862

FIGURE 2.

FIGURE 2

Provitamin A biosynthesis. Enzymes involved in its biosynthesis are marked in blue. Connections to other vitamin pathways are indicated in red. Filled yellow boxes indicate the external influences on the biosynthesis, affected enzymes surrounded by a yellow square. The regulatory influences on DXS are derived from studies on Arabidopsis (Estevez et al., 2001), those on PSY from studies in maize, rice and tomato (Li F.Q. et al., 2008; Welsch et al., 2008). Cofactors are encircled in gray. Abbreviations (in order of appearance in the pathway): G3P, glyceraldehyde-3-phosphate; DXS, 1-deoxy-D-xylulose-5-phosphate synthase; DXP, 1-deoxy-D-xylulose-5-phospate; DXR, DXP reductoisomerase; IPP, isopentenyl diphosphate isomerase; IDI, isopentenyl diphosphate isomerase; DMAPP, dimethylallyl diphosphate; GGPPS, geranylgeranyl diphosphate synthase; GGPP, geranylgeranyl diphosphate; PSY, phytoene synthase; PDS, phytoene desaturase; ZISO, ζ-carotene isomerase; ZDS, ζ-carotene desaturase; CRTISO, carotene isomerase; β-LCY, lycopene-β-cyclase; 𝜀-LCY, lycopene-𝜀-cyclase; BCH1, β-carotene hydroxylase; ZEP1, zeaxanthin epoxidase; VDE, violaxanthin de-epoxidase; AsA, ascorbate.