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MetaCyc Pathway: luteolin biosynthesis
Inferred from experiment

Enzyme View:

Pathway diagram: luteolin biosynthesis

This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Superclasses: BiosynthesisSecondary Metabolites BiosynthesisPhenylpropanoid Derivatives BiosynthesisFlavonoids BiosynthesisFlavones Biosynthesis

Some taxa known to possess this pathway include : Arabidopsis thaliana col, Gerbera hybrid cultivar, Oryza sativa, Perilla frutescens, Petroselinum crispum

Expected Taxonomic Range: Magnoliophyta

General Background

Flavones such as apigenin and luteolin represent one of the most abundant and important subclasses of the 9000 flavonoids described so far [Martens99]. Flavones belong to the most widespread compounds in plants and have been found in all major land-plant lineages.

The biosynthesis of flavones has been studied intensively because of their contribution to unique physiological and developmental processes in plants. Luteolin has a defined role as a signalling molecule involved in the induction and expression of nodulation genes [Peters86]. Flavones in general have been demonstrated to be significantly involved in the evolvement of the preferred attractant for bee pollinators, i.e. blue flower colours which are restricted to the higher developed angiosperm plant families [Harborne00]. In addition, flavones possess antioxidative activity [Lukacin01] frequently employed in the prevention of cancer and coronary heart disease [Martens05].

About This Pathway

The oxidation of flavanones to flavones is catalyzed by flavone synthases introducing a double bound between the C atoms 2 and 3 of the C-ring. Interestingly, the biosynthesis of flavone is carried out by two completely different flavone synthases, i.e. flavone synthase I (EC and flavone synthase II.

While flavone synthase II (FNS II), a membrane bound cytochrome P450 dependent monooxygenase is found in many plant families the soluble dioxygenase flavone synthase I (FNS I) has only been isolated from members of the Apiacea family to date [Britsch90]. FNS I belongs to the family of 2-oxoglutarate-dependent dioxygenases which are involved in many different metabolic processes of plants, bacteria, fungi and animals [Lukacin01]. Among the five 2-oxoglutarate-dependent enzymes involved in flavonoid biosynthesis (compare flavonol biosynthesis) FNS I is considered highly pathway specific because of its distinct substrate specificity [Martens03].

The flavone synthases I and II catalyze the 2,3-desaturation of the flavanone in one step, i.e. the formation of apigenin from naringnin and luteollin from eriodictyol, respectively (this pathway). Although it had been suggested that FSN I may catalyze a sequential C3 hydroxylation and dehydration a vicinal desaturation without the release of a free intermediate was experimentally verified [Martens03]. The formation of the dihydroxylated B-ring compound luteolin requires an additional hydroxylation step carried out by the cytochrome P450 dependent monooxygenase flavonoid 3'(β)-hydroxylase [Kitada01] [Ueyama02]. The two possible routes leading to luteolin (via eridictyol or apigenin) are displayed in this pathway.

Unification Links: AraCyc:PWY-5060

Created 05-Dec-2005 by Foerster H, TAIR
Revised 23-Jan-2013 by Foerster H, Boyce Thompson Institute


Britsch90: Britsch L (1990). "Purification and characterization of flavone synthase I, a 2-oxoglutarate-dependent desaturase." Arch Biochem Biophys 282(1);152-60. PMID: 2221917

Harborne00: Harborne JB, Williams CA (2000). "Advances in flavonoid research since 1992." Phytochemistry 55(6);481-504. PMID: 11130659

Kitada01: Kitada C, Gong Z, Tanaka Y, Yamazaki M, Saito K (2001). "Differential expression of two cytochrome P450s involved in the biosynthesis of flavones and anthocyanins in chemo-varietal forms of Perilla frutescens." Plant Cell Physiol 42(12);1338-44. PMID: 11773526

Lukacin01: Lukacin R, Matern U, Junghanns KT, Heskamp ML, Britsch L, Forkmann G, Martens S (2001). "Purification and antigenicity of flavone synthase I from irradiated parsley cells." Arch Biochem Biophys 393(1);177-83. PMID: 11516175

Martens03: Martens S, Forkmann G, Britsch L, Wellmann F, Matern U, Lukacin R (2003). "Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley." FEBS Lett 544(1-3);93-8. PMID: 12782296

Martens05: Martens S, Mithofer A (2005). "Flavones and flavone synthases." Phytochemistry 66(20);2399-407. PMID: 16137727

Martens99: Martens S, Forkmann G (1999). "Cloning and expression of flavone synthase II from Gerbera hybrids." Plant J 20(5);611-8. PMID: 10652133

Peters86: Peters NK, Frost JW, Long SR (1986). "A plant flavone, luteolin, induces expression of Rhizobium meliloti nodulation genes." Science 1986;233(4767);977-80. PMID: 3738520

Ueyama02: Ueyama Y, Fukuchi-Mizutani M, Fukui Y, Miyazaki K, Ohkawa H, Kusumi T, Tanaka Y (2002). "Molecular and biochemical characterization of torenia flavonoid 3'-hydroxylase and flavone synthase II and modification of flower color by modulating the expression of these genes." Plant Science, 163, 253-263.

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Berim13: Berim A, Gang DR (2013). "The roles of a flavone-6-hydroxylase and 7-O-demethylation in the flavone biosynthetic network of sweet basil." J Biol Chem 288(3);1795-805. PMID: 23184958

Bredebach11: Bredebach M, Matern U, Martens S (2011). "Three 2-oxoglutarate-dependent dioxygenase activities of Equisetum arvense L. forming flavone and flavonol from (2S)-naringenin." Phytochemistry 72(7);557-63. PMID: 21353683

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Lee08a: Lee YJ, Kim JH, Kim BG, Lim Y, Ahn JH (2008). "Characterization of flavone synthase I from rice." BMB Rep 41(1);68-71. PMID: 18304453

Martens01: Martens S, Forkmann G, Matern U, Lukacin R (2001). "Cloning of parsley flavone synthase I." Phytochemistry 58(1);43-6. PMID: 11524111

Martens98: Martens S, Forkmann G (1998). "Genetic control of flavone synthase II activity in flowers of Gerbera hybrids." Phytochemistry, 49(7), 1953-1958.

Schoenbohm00: Schoenbohm C, Martens S, Eder C, Forkmann G, Weisshaar B (2000). "Identification of the Arabidopsis thaliana flavonoid 3'-hydroxylase gene and functional expression of the encoded P450 enzyme." Biol Chem 2000;381(8);749-53. PMID: 11030432

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.5 on Sun May 1, 2016, BIOCYC11A.