Multifunctional enzyme involved in the biosynthesis of the indole-derived phytoalexin camalexin. Catalyzes two reactions, the formation of dihydrocamalexate from indole-3-acetonitrile-cysteine conjugate and the oxidative decarboxylation of dihydrocamalexate which is the final step in camalexin biosynthesis (Ferrari et al. 2003)