Abstract
Isoflavone synthase activity was tested with a microsomal preparation of the cell cultures of Pueraria lobata that had been treated with an endogenous elicitor prepared by hydrolysis of their own cell walls with a fungal endopolygalacturonase. The deoxy types of flavanone and chalcone, liquiritigenin and isoliquiritigenin, were both converted into the corresponding isoflavone, deidzein, by a microsomal preparation. Competitive experiments with [3H]flavanone and [14C]chalcone revealed that flavanone is the direct substrate of this isoflavone synthase. Kinetic experiments indicated that liquiritigenin is a much more favorable substrate than naringenin.
