Production of three O-methhylated esculetins with Escherichia coli expressing O-methyltransferase from poplar.

O-Methyltransferase, POMT-9 was expressed in Escherichia coli. HPLC analysis of reaction products revealed three peaks corresponding to isoscopoletin, scopoletin, and scoparone, and their structures were determined using NMR. Biotransformation of esculetin with E. coli expressing POMT-9 generated scopoletin, isoscopoletin, and scoparone at 30.3, 21, and 31 microM respectively. POMT-9 is the first O-methyltransferase that produces three different O-methylated products.