Engineering isoflavone metabolism with an artificial bifunctional enzyme

L. Tian, R. A. Dixon

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Plant secondary metabolism has been a focus of research in recent years due to its significant roles in plant defense and in human medicine and nutrition. A protein engineering strategy was designed to more effectively manipulate plant secondary metabolite (isoflavonoid) biosynthesis. A bifunctional isoflavone synthase/chalcone isomerase (IFS/CHI) enzyme was constructed by in-frame gene fusion, and expressed in yeast and tobacco. The fusion protein was targeted to the endoplasmic reticulum (ER) membrane and the individual enzymatic functions of its component fragments were retained when assayed in yeast. Petals and young leaves of IFS/CHI transgenic tobacco plants produced higher levels of the isoflavone genistein and genistein glycosides as a ratio of total flavonoids produced than did plants transformed with IFS alone. Thus, through a combined molecular modeling, in vitro protein engineering and in planta metabolic engineering approach, it was possible to increase the potential for accumulation of isoflavonoid compounds in non-legume plants. Construction of bifunctional enzymes will simplify the transformation of plants with multiple pathway genes, and such enzymes may find broad uses for enzyme (e.g., cytochrome P450 family) and biochemical pathway engineering.

Original languageEnglish (US)
Pages (from-to)496-507
Number of pages12
Issue number3
StatePublished - Aug 2006
Externally publishedYes


  • Chalcone isomerase
  • Cytochrome P450
  • Fusion enzyme
  • Isoflavone synthase
  • Legume
  • Metabolic engineering

ASJC Scopus subject areas

  • Plant Science


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