Publications

• Flavonoid 3'-O-methyltransferase from rice: cDNA cloning, characterization and functional expression.

  Kim B.-G., Lee Y., Hur H.-G., Lim Y., Ahn J.-H.

  Plant O-methyltransferases (OMTs) are known to be involved in methylation of plant secondary metabolites, especially phenylpropanoid and flavonoid compounds. An OMT, ROMT-9, was cloned and characterized from rice using a reverse transcriptase polymerase chain reaction (RT-PCR). The blast results f ... >> More

  Plant O-methyltransferases (OMTs) are known to be involved in methylation of plant secondary metabolites, especially phenylpropanoid and flavonoid compounds. An OMT, ROMT-9, was cloned and characterized from rice using a reverse transcriptase polymerase chain reaction (RT-PCR). The blast results for ROMT-9 showed a 73% identity with caffeic acid OMTs from maize and Triticum aestivum. ROMT-9 was expressed in Escherichia coli and its recombinant protein was purified using affinity chromatography. It was then tested for its ability to transfer the methyl group of S-adenosyl-l-methionine to the flavonoid substrates, eriodictyol, luteolin, quercetin, and taxifolin, all of which have a 3'-hydroxyl functional group. The reaction products were analyzed using TLC, HPLC, HPLC/MS, and NMR spectroscopy. The NMR analysis showed that ROMT-9 transferred the methyl group specifically to the 3'-hydroxyl group of quercetin, resulting in the formation of its methoxy derivative. Furthermore, ROMT-9 converted flavonoids containing the 3'-hydroxy functional group such as eriodictyol, luteolin, quercetin and taxifolin into the corresponding methoxy derivatives, suggesting that ROMT-9 is an OMT with strict specificity for the 3'-hydroxy group of flavonoids. << Less

  Phytochemistry 67:387-394(2006) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Biosynthesis of homoeriodictyol from eriodictyol by flavone 3'-O-methyltransferase from recombinant Yarrowia lioplytica: Heterologous expression, biochemical characterization, and optimal transformation.

  Liu Q., Liu L., Zhou J., Shin H.D., Chen R.R., Madzak C., Li J., Du G., Chen J.

  In this work, we attempted to synthesize homoeriodictyol by transferring one methyl group of S-adenosyl-L-methionine (SAM) to eriodictyol using flavone 3'-O-methyltransferase ROMT-9, which was produced by recombinant Yarrowia lipolytica. Specifically, the ROMT-9 gene from rice was synthesized and ... >> More

  In this work, we attempted to synthesize homoeriodictyol by transferring one methyl group of S-adenosyl-L-methionine (SAM) to eriodictyol using flavone 3'-O-methyltransferase ROMT-9, which was produced by recombinant Yarrowia lipolytica. Specifically, the ROMT-9 gene from rice was synthesized and cloned into the multi-copy integrative vector pINA1297, and was further expressed in Y. lipolytica with a growth phase-dependent constitutive promoter hp4d. The highest ROMT-9 activity reached 5.53 U/L after 4 days of culture in shake flask. The optimal pH and temperature of the purified ROMT-9 were 8.0 and 37 °C, respectively. The purified enzyme was stable up to 40 °C, and retained more than 80% of its maximal activity between pH 6.5 and 9.0. The recombinant ROMT-9 did not require Mg²⁺ for catalysis, while was completely inhibited in the presence of 5 mM Zn²⁺, Cu²⁺, Ba²⁺, Al³⁺, or Ni²⁺. The purified ROMT-9 was used to synthesize homoeriodictyol, and the maximal transformation ratio reached 52.4% at 16 h under the following conditions: eriodictyol 0.2 g/L, ROMT-9 0.16 g/L, SAM 0.2 g/L, CH₃OH 6% (v/v), temperature 37 °C, and pH 8.0. This work provides an alternative strategy for efficient synthesis of homoeriodictyol and compared to the traditional plant extraction or chemical synthesis, the biotransformation approach generates less environmental pollution and has a great potential for the sustainable production of homoeriodictyol. << Less

  J Biotechnol 167:472-478(2013) [PubMed] [EuropePMC]