Flavone and Flavonol Methyltransferases

Methylation has been reported at all available hydroxyls of flavones and flavonols (the C-5, -6, -7, -8, -2, -3, -4, and -5 positions), and it can occur on both aglycone and glycoside substrates. Many of the corresponding enzyme activities have been described in detail, and typically show strong preferences with regard to substrate type and the position methylated. Recently, cDNA sequences have been identified for several flavonoid OMTs, allowing sequence-based analysis and examination of recombinant protein activities. All are members of the SAM-MT family described in Section 3.4.9.2. 

A cDNA for an OMT (PFOMT) with wide substrate acceptance that includes flavonols and HCA derivatives has been identified from Mesembryanthemum crystallinum (ice plant). 

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