Enzymatic synthesis of 6'-deoxychalcone in cultured Glycyrrhiza echinata cells.

5-Deoxy-(iso)flavonoids are biosynthesized from 6'-deoxychalcone (isoliquiritigenin). The coaction of a reductase with chalcone synthase (CHS) has been established in soybean cells to be responsible for the synthesis of 6'-deoxychalcone. Western blot analysis of crude extracts from cultured cells of Glycyrrhiza echinata, another member of the Leguminosae, revealed proteins which cross-react with an antiserum raised against the soybean reductase. DEAE-Cellulose chromatography of the extract yielded fractions which showed CHS activity but not deoxychalcone synthase activity, and these fractions were also negative in Western blot analysis. In contrast, fractions displaying positive signals with the antiserum were also able to synthesize 6'-deoxychalcone/5-deoxyflavanone. These results indicate that in G. echinata, too, synthesis of 6'-deoxychalcone is likely to be performed by the coaction of the reductase and CHS. Induction of the reductase and CHS by yeast extract treatment of the cells was demonstrated.