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
- Research Support, Non-U.S. Gov't
MeSH terms
- Amino Acid Sequence
- Animals
- Cloning, Molecular
- Expressed Sequence Tags
- Flavanones*
- Flavonoids / metabolism
- Gene Expression Regulation, Plant
- Genistein / metabolism
- Glycine max / cytology
- Glycine max / enzymology*
- Glycine max / genetics
- Hydroxylation
- Insecta / cytology
- Insecta / genetics
- Isoflavones / metabolism*
- Kinetics
- Medicago sativa / cytology
- Medicago sativa / enzymology
- Medicago sativa / genetics
- Microsomes / enzymology
- Microsomes / metabolism
- Molecular Sequence Data
- Oxygenases / chemistry
- Oxygenases / genetics
- Oxygenases / metabolism*
- Recombinant Proteins / biosynthesis
- Recombinant Proteins / metabolism
Substances
- Flavanones
- Flavonoids
- Isoflavones
- Recombinant Proteins
- isoflavanone
- daidzein
- Genistein
- Oxygenases
- isoflavone synthase
- naringenin
- liquiritigenin
Associated data
- GENBANK/AF135484
- GENBANK/AF135485