Isolation of pterocarpan synthase, the terminal enzyme of pterocarpan phytoalexin biosynthesis in cell suspension cultures of Cicer arietinum

Chickpea (Cicer arietinum L.) cell suspension cultures transferred into a medium containing yeast extract as elicitor accumulate the phytoalexins medicarpin and maackiain. Concomitant with the accumulation of the pterocarpans, a new enzyme activity is induced which catalyses the conversion of the 2′‐hydroxyisoflavanone vestitone to the pterocarpan medicarpin. Maximum enzyme activity was reached 12 h after transfer of cells and then activity declined. The soluble enzyme was partially purified and characterized as pterocarpan synthase.