A regio-specific 4 <i>’</i> - <i>O</i> -methyltransferase from <i>Epimedium pseudowushanense</i>  regiospecifically catalyzing 8-prenylkeampferol to icaritin

<i>Epimedium</i> is widely used in traditional Chinese medicine and contains rich bioactive compounds. These compounds often have a methyl group at their 4'-OH position catalyzed by methyltransferases. Therefore, studying methyltransferases in <i>Epimedium</i> plants is of great significance. In this study, a flavonol methyltransferase, EpOMT4, was isolated from <i>Epimedium pseudowushanense</i> B.L. Guo. The recombinant enzyme regiospecifically transferred a methyl group to the 4'-OH position of 8-prenylkaempferol forming icaritin. The study demonstrates that enzymatic methylation of flavonoids in <i>Epimedium</i> plants holds significant potential and could provide a promising alternative method for the biosynthetic production of bioactive methylated prenylflavonoids.