Characterization of flavone synthase I from rice

BMB Rep. 2008 Jan 31;41(1):68-71. doi: 10.5483/bmbrep.2008.41.1.068.


Flavones are synthesized from flavanones through the action of flavone synthases (FNSs). There are two FNSs, FNS I and II. FNS I is a soluble dioxygenase present in members of the Apiaceae family and FNS II is a membrane bound cytochrome P450 enzyme that has been identified in numerous plant species. In this study, we cloned OsFNS I-1 from rice by RTPCR, expressed it in E. coli, and purified the recombinant protein. By NMR analysis, we found that OsFNS I-1 converted the flavanone (2S)-naringenin into the flavone, apigenin. Moreover, we found that the cofactors oxoglutarate, FeSO(4), ascorbate and catalase are required for this reaction. OsFNS I-1 encodes a flavone synthase I. This is the first type I FNS I found outside of the Apiaceae family.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chromatography, High Pressure Liquid
  • Escherichia / genetics
  • Flavanones / chemistry
  • Mixed Function Oxygenases / chemistry*
  • Mixed Function Oxygenases / genetics*
  • Molecular Sequence Data
  • Oryza / enzymology*
  • Oryza / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment


  • Flavanones
  • Mixed Function Oxygenases
  • flavone synthase I
  • naringenin