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:||Biosynthesis → Secondary Metabolites Biosynthesis → Phenylpropanoid Derivatives Biosynthesis → Flavonoids Biosynthesis → Isoflavonoids Biosynthesis|
|Biosynthesis → Secondary Metabolites Biosynthesis → Phytoalexins Biosynthesis → Isoflavonoid Phytoalexins Biosynthesis|
Expected Taxonomic Range: Fabaceae
Glyceollins are the main phytoalexins found in soybean (Glycine max). Consistent with most of the isoflavonoid derived phytoalexins, glyceollins are induced in response to plant pathogens [Boue00] [Hagmann84] and related stress [Landini03].
The initial enzymatic steps of the glyceollin biosynthesis parallel the biosynthesis of medicarpin and maackiain. In contrast to those simple pterocarpans the complex prenylated pterocarpans (phaseollin, glyceollin) also derive from the 5-deoxyisoflavone daidzein but do not involve a methoxylation step during their biosynthesis.
Glycinol, the final compound in this part of the glyceollin pathway, is stereospecifically hydroxylated at the 6a position resulting in the (-) or (6aS,11aS)-3,6a,9-configuration of this compound [Hagmann84]. The remaining enzymatic reactions maintain the given configuration as demonstrated for other pathways that involve a pterocarpan-6a-hydroxylase in their biosynthesis (e.g. pisatin) [Kochs89].
Superpathways: superpathway of pterocarpan biosynthesis (via daidzein)
Hagmann84: Hagmann ML, Heller W, Grisebach H (1984). "Induction of phytoalexin synthesis in soybean. Stereospecific 3,9-dihydroxypterocarpan 6a-hydroxylase from elicitor-induced soybean cell cultures." Eur J Biochem 142(1);127-31. PMID: 6540173
Kochs89: Kochs G, Grisebach H (1989). "Phytoalexin synthesis in soybean: purification and reconstitution of cytochrome P450 3,9-dihydroxypterocarpan 6a-hydroxylase and separation from cytochrome P450 cinnamate 4-hydroxylase." Arch Biochem Biophys 273(2);543-53. PMID: 2505672
Akashi98: Akashi T, Aoki T, Ayabe S (1998). "CYP81E1, a cytochrome P450 cDNA of licorice (Glycyrrhiza echinata L.), encodes isoflavone 2'-hydroxylase." Biochem Biophys Res Commun 251(1);67-70. PMID: 9790908
Bless88: Bless W, Barz W, (1988) "Isolation of pterocarpan synthase, the terminal enzyme of pterocarpan phytoalexin biosynthesis in cell suspension cultures of Cicer arietinum." FEBS Letters (1988), 235(1), 47-50.
Ebel86: Ebel J, Grisebach H, Bonhoff A, Grab D, Hoffmann C, Kochs G, Mieth H, Schmidt W, Staeb M, (1986) "Phytoalexin synthesis in soybean following infection of roots with Phytophtora megasperma or treatment of cell cultures with fungal elicitors." In: Lugtenberg, B. (editor) Regocnition in microbe-plant symbiotic and pathogenic interactions (1986), NATO ASI series, series H: cell biology, Vol. 4, 345-361, Springer-Verlag Berlin Heidelberg New York London Paris Tokyo.
Fischer90: Fischer D, Ebenau-Jehle C, Grisebach H (1990). "Phytoalexin synthesis in soybean: purification and characterization of NADPH:2'-hydroxydaidzein oxidoreductase from elicitor-challenged soybean cell cultures." Arch Biochem Biophys 276(2);390-5. PMID: 2306102
Fischer90a: Fischer D, Ebenau-Jehle C, Grisebach H, (1990) "Purification and characterization of pterocarpan synthase from elicitor-challenged soybean cell cultures." Phytochemistry (1990), 29(9), 2879-2882.
Gunia: Gunia W, Hinderer W, Wittkampf U, Barz W, (1991) "Elicitor induction of cytochrome P-450 monooxygenases in cell suspension cultures of chickpea (Cicer arietinum L.) and their involvement in pterocarpan phytoalexin biosynthesis." Z. Naturforsch. 46c, 58-66.
Guo94: Guo L, Dixon RA, Paiva NL (1994). "Conversion of vestitone to medicarpin in alfalfa (Medicago sativa L.) is catalyzed by two independent enzymes. Identification, purification, and characterization of vestitone reductase and 7,2'-dihydroxy-4'-methoxyisoflavanol dehydratase." J Biol Chem 269(35);22372-8. PMID: 8071365
Guo94a: Guo L, Dixon RA, Paiva NL (1994). "The 'pterocarpan synthase' of alfalfa: association and co-induction of vestitone reductase and 7,2'-dihydroxy-4'-methoxy-isoflavanol (DMI) dehydratase, the two final enzymes in medicarpin biosynthesis." FEBS Lett 356(2-3);221-5. PMID: 7805842
Hinderer: Hinderer W, Flentje U, Barz W, (1987) "Microsomal isoflavone 2'- and 3'-hydroxylases from chickpea (Cicer arietinum L.) cell suspensions induced for pterocarpan phytoalexin formation." FEBS Letters, 214(1), 101-106.
Kochs92: Kochs G, Werck-Reichhart D, Grisebach H (1992). "Further characterization of cytochrome P450 involved in phytoalexin synthesis in soybean: cytochrome P450 cinnamate 4-hydroxylase and 3,9-dihydroxypterocarpan 6a-hydroxylase." Arch Biochem Biophys 293(1);187-94. PMID: 1731635
Paiva91: Paiva NL, Edwards R, Sun YJ, Hrazdina G, Dixon RA (1991). "Stress responses in alfalfa (Medicago sativa L.) 11. Molecular cloning and expression of alfalfa isoflavone reductase, a key enzyme of isoflavonoid phytoalexin biosynthesis." Plant Mol Biol 17(4);653-67. PMID: 1912490
Paiva94: Paiva NL, Sun Y, Dixon RA, VanEtten HD, Hrazdina G (1994). "Molecular cloning of isoflavone reductase from pea (Pisum sativum L.): evidence for a 3R-isoflavanone intermediate in (+)-pisatin biosynthesis." Arch Biochem Biophys 312(2);501-10. PMID: 8037464
Schopfer98: Schopfer CR, Kochs G, Lottspeich F, Ebel J (1998). "Molecular characterization and functional expression of dihydroxypterocarpan 6a-hydroxylase, an enzyme specific for pterocarpanoid phytoalexin biosynthesis in soybean (Glycine max L.)." FEBS Lett 432(3);182-6. PMID: 9720921
Tiemann91: Tiemann K, Inze D, Van Montagu M, Barz W (1991). "Pterocarpan phytoalexin biosynthesis in elicitor-challenged chickpea (Cicer arietinum L.) cell cultures. Purification, characterization and cDNA cloning of NADPH:isoflavone oxidoreductase." Eur J Biochem 200(3);751-7. PMID: 1915347
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