Lycopene epsilon cyclase

RONEN G, COHEN M, ZAMIR D and HIRSCHBERG J (1999) Regnlation of carotenoid biosynthesis during tomato fruit development expression of the gene for lycopene epsilon cyclase is down regulated during ripening and is elevated in the mutant delta . Plant J, 17, 341-51. 

Kato, M. et al.. Accumulation of carotenoids and expression of carotenoid biosynthetic genes during maturation in citrus fruit. Plant Physiol. 134, 82, 2004. Cunningham, F.X. Jr. and Gantt, E., One ring or two Determination of ring number in carotenoids by lycopene epsilon-cyclases, Ptvc. Natl. Acad. Sci. USA 98, 2905, 2001. 

Diretto, G. et al.. Metabolic engineering of potato tuber carotenoids through tuber-specihc silencing of lycopene epsilon cyclase, BMC Plant Biol. 6, 13, 2006. 

Fig. 5.3 Carotenoid biosynthesis in maize endosperm. Compounds IPP, isopentenyl pyrophosphate FPP, famesyl pyrophosphate GGPP, geranylgeranyl pyrophosphate DMAPP, dimethallyl pyrophosphate. Carotenoid biosynthetic pathway enzymes PSY, phytoene synthase PDS, phytoene desaturase ZDS, zetacarotene desaturase ISO, carotene isomerase LCY-B, lycopene beta cyclase LCY-E, lycopene epsilon cyclase HYD-B, beta-carotene hydroxylase HYD-E, alpha-carotene hydroxylase Isonrenoid biosynthetic pathway enzymes IPPI (IPP isomerase) GGPPS (GGPP synthase). Structures are not representative of the geometrical isomer substrates (e.g. Z-phytoene is a bent structure).

Fig. 56.2 Carotenoid biosynthesis pathway in plants. Enzymes (with abbreviations) indicated are isopentenyl pyrophosphate isomerase (IPI), geranylgeranyl pyrophosphate synthase (GGPS), phytoene synthase (PSY), phytoene desaturase (PDS), zeta-carotene desaturase (ZDS), carotenoid isomerase (CRTISO), lycopene beta-cyclase (LCYB), lycopene epsilon-cyclase (LCYE), beta-ring carotene hydroxylase (CHXB), epsilon-ring carotene hydroxylase (CHXE), zeaxanthin epoxidase (ZEP), violaxanthin de-epoxidase (VDE), capsorubin-capsanthin synthase (CCS), neoxanthin synthase (NXS), 9-cis epoxycarotenoid dioxygenase (NCED), and carotenoid cleavage dioxygenase (CCD). (Source [101], drawn using KeGG pathway)...

Yu B, Lydiate D, Young L, Schafer U, Hannoufa A (2008) Enhancing the carotenoid content of Brassica napus seeds by downregulating lycopene epsilon cyclase. Transgenic Res 17 573-585... 

Cunningham, F.X. Jr. et al.. Functional analysis of the beta and epsilon lycopene cyclase enzymes of Arabidopsis reveals a mechanism for control of cyclic carotenoid formation. Plant Cell 8, 1613, 1996. 

Bishop N I, Urbig T and Senger H (1995) Complete separation of the beta, epsilon- and beta, beta-carotenoid biosynthetic pathways by a unique mutation of the lycopene cyclase in the green alga, Scenedesmus obliquus. FEBS Letters 367 158-162... 

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