S. Ayabe, T. Yoshikawa, Miyuki Kobayashi
1980
Citations
1
Influential Citations
26
Citations
Journal
Phytochemistry
Abstract
Abstract In order to clarify the O -methylation step in the biosynthesis of a retrochalcone, echinatin(4,4′-dihydroxy-2-methoxychalcone), methyl transfer from S -adenosyl- l -methionine (SAM) to licodione (1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)-1,3-propanedione) in the cell-free extract of the cultured cells of Glycyrrhiza echinata was examined. Time course of methyl transferring activity during culture cycle in 4 strains was correlated to echinatin content. The enzyme catalysing this reaction, licodione O -methyltransferase (LMT), was purified 135-fold. Substrate specificity studies implied that the hydroxy group ortho to the C 3 linkage in licodione was methylated in this reaction. O -Methyl-licodiones were synthesized for comparison and the sole product of LMT-catalysed reaction was identified as 2′- O -methyl-licodione. A possible scheme for the last steps of echinatin biosynthesis is proposed.