A new enzyme,S-adenosyl-L-methionine:flavonoid 4¢-O-methyltransferase (EC )(F 4¢-OMT), has been puri-fied 1 399-fold from the tissues of carnation (Dianthus caryophyllus L). The enzyme, with a molecular mass of 43–45 kDa and a pI of , specifically methylates the hydroxysubstituent in4¢-positionof theflavones, flavanones and isoflavones in the presence ofS-adenosyl-L-methionine. A high affinity for the flavone kaempferol was observed (Km¼;Vmax¼ )1 Æmg )1 ), while other 4¢-hydroxylated flavonoids proved likewise to be suitable substrates
