Lycopene, biosynthesis

Alper H, Jin YS, Moxley JF et al (2005) Identifying gene targets for the metabolic engineering of lycopene biosynthesis in Escherichia coli. Metab Eng 7 155-164... 

Feofilova, E.P., Tereshina, V.M., and Memorskaya, A.S. 1995. Regulation of lycopene biosynthesis in mucorous fungus Blakeslea trispora by pyridine derivatives. Mikrobiologiya 64 734-740. 

It should be mentioned in this connection that in tobacco tissue cultures, to be sure only in the presence of naphthalene-1-acetic acid, CCC affected a strong increase in lycopene biosynthesis and accumulation (Eef. 

PhytoAuen an aliphatic polyisoprenoid hydrocarbon carotenoid, Af, 548. P. contains ten double bonds (five of them conjugated), six branch methyl groups and two terminal isopropylidene groups. As in phytoene, the central double bond between Cl 5 and C16 has cis configuration. P. is found widely in plants, e.g. tomatoes and carrots, and it is an intermediate in lycopene biosynthesis (see Tetraterpenes). 

Jin, Y.S. and Stephanopoulos, G. (2007) Multi-dimensional gene target search for improving lycopene biosynthesis... 

Carotenoids are natural pigments characterized by a tail to tail linkage between two C20 units and an extended conjugated system of double bonds They are the most widely dis tributed of the substances that give color to our world and occur m flowers fruits plants insects and animals It has been estimated that biosynthesis from acetate produces approximately a hundred million tons of carotenoids per year The most familiar carotenoids are lycopene and (3 carotene pigments found m numerous plants and easily isolable from npe tomatoes and carrots respectively... 

Clearly, the control of gene expression at the transcriptional level is a key regulatory mechanism controlling carotenogenesis in vivo. However, post-transcriptional regulation of carotenoid biosynthesis enzymes has been found in chromoplasts of the daffodil. The enzymes phytoene synthase (PSY) and phytoene desaturase (PDS) are inactive in the soluble fraction of the plastid, but are active when membrane-bound (Al-Babili et al, 1996 Schledz et al, 1996). The presence of inactive proteins indicates that a post-translational regulation mechanism is present and is linked to the redox state of the membrane-bound electron acceptors. In addition, substrate specificity of the P- and e-lycopene cyclases may control the proportions of the p, P and P, e carotenoids in plants (Cunningham et al, 1996). 

The carotenoid pathway may also be regulated by feedback inhibition from the end products. Inhibition of lycopene cyclisation in leaves of tomato causes increase in the expression of Pds and Psy-1 (Giuliano et al, 1993 Corona et al, 1996). This hypothesis is supported by other studies using carotenoid biosynthesis inhibitors where treated photosynthetic tissues accumulated higher concentrations of carotenoids than untreated tissues (reviewed by Bramley, 1993). The mechanism of this regulation is unknown. A contrary view, however, comes from studies on the phytoene-accumulating immutans mutant of Arabidopsis, where there is no feedback inhibition of phytoene desaturase gene expression (Wetzel and Rodermel, 1998). 

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. 

Desaturation and Isomerization to Coeored Carotenoids Biosynthesis of Lycopene... 

Plant apocarotenoids have a wide variety of structures and functions. As expected, there is a small gene family of CCDs with different cleavage sites and somewhat promiscuous substrate selection. Some CCDs are stereo-specific, for example, 9-cis epoxycarotenoids are the substrates for NCEDs (9-cis expoxy dioxygenases) that produce the precursor of ABA biosynthesis, xanthoxin. Both linear carotenoids (lycopene) and cyclic carotenoids are substrates for cleavage at various double bonds including the central 15-15 and eccentric 5-6, 7-8, 9-10, 9 -10, and 11-12 bonds. Some CCDs cleave both linear and cyclic carotenoids and may cleave the same molecule twice, e.g., both 9-10 and 9 -10 positions. 

Cunningham, F.X. Jr. et ah. Cloning and functional expression in Escherichia coli of a cyanobacterial gene for lycopene cyclase, the enzyme that catalyzes the biosynthesis of beta-carotene, FEBS Lett. 328, 130, 1993. 

Breitenbach, J., Vioque, A., and Sandmann, G., Gene sll0033 from Synechocystis 6803 encodes a carotene isomerase involved in the biosynthesis of aU-E lycopene,... 

Edwards JI, Saltveit ME and Henderson WR. 1983. Inhibition of lycopene synthesis in tomato pericarp tissue by inhibitors of ethylene biosynthesis and reversal with applied ethylene. J Am Soc Hort Sci... 

Biosynthesis and Metabolism.—Pathways and Reactions. Two reviews of carotenoid biosynthesis discuss, respectively, the early steps and the later reactions." The former paper deals with the mechanism of formation of phytoene and the series of desaturation reactions by which phytoene is converted into lycopene, and also describes in detail the biosynthesis of bacterial C30 carotenoids. The second paper" presents details of the mechanism and stereochemistry of cyclization and the other reactions that involve the carotenoid C-1 —C-2 double bond and the later modifications, especially the introduction of oxygen functions. 

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