Catalyzes the hydrogen peroxide-dependent dimerization of two L-tryptophan-derived molecules (imine form of indole 3-pyruvate (IPA)), to form an uncharacterized product suggested to be indole-3-pyruvate imine dimer that can spontaneously convert into dichlorochromopyrrolate (CPA). The uncharacterized product is the substrate of VioE. 2 H2O2 = 2 H2O + O2 2 2-iminio-3-(indol-3-yl)propanoate + H2O2 = 2 H2O + indole-3-pyruvate imine dimer Pigment biosynthesis; violacein biosynthesis. By N-acylhomoserine lactone (AHL). Violacein production is used as a biosensor for the detection of quorum-sensing AHL production. Violacein possesses antibacterial, antiviral, antimicrobial, antileishmanial, trypanocidal and potential antitumoral activities.