Abstract
The first specific reaction in the biosynthesis of isoflavonoid compounds in plants is the 2-hydroxylation, coupled to aryl migration, of a flavanone. Using a functional genomics approach, we have characterized a cDNA encoding a 2-hydroxyisoflavanone synthase from soybean (Glycine max). Microsomes isolated from insect cells expressing this cytochrome P450 from a baculovirus vector convert 4', 7-dihydroxyflavanone (liquiritigenin) to 4',7-dihydroxyisoflavone (daidzein), most likely via 2,4',7-trihydroxyisoflavanone which spontaneously dehydrates to daidzein. The enzyme also converts naringenin (4',5,7-trihydroxyflavanone) to genistein, but at a lower rate. 2-Hydroxyisoflavanone synthase transcripts are strongly induced in alfalfa cell suspensions in response to elicitation.
Copyright 1999 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Cloning, Molecular
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Expressed Sequence Tags
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Flavanones*
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Flavonoids / metabolism
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Gene Expression Regulation, Plant
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Genistein / metabolism
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Glycine max / cytology
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Glycine max / enzymology*
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Glycine max / genetics
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Hydroxylation
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Insecta / cytology
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Insecta / genetics
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Isoflavones / metabolism*
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Kinetics
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Medicago sativa / cytology
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Medicago sativa / enzymology
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Medicago sativa / genetics
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Microsomes / enzymology
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Microsomes / metabolism
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Molecular Sequence Data
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Oxygenases / chemistry
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Oxygenases / genetics
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Oxygenases / metabolism*
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / metabolism
Substances
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Flavanones
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Flavonoids
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Isoflavones
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Recombinant Proteins
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isoflavanone
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daidzein
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Genistein
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Oxygenases
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isoflavone synthase
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naringenin
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liquiritigenin
Associated data
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GENBANK/AF135484
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GENBANK/AF135485