Transcription factor; part of the L-tyrosine degradation gene cluster that mediates the biosynthesis of the brownish pigment pyomelanin as an alternative melanin (PubMed:19028908, PubMed:22046314). Acts as a transcriptional activator for the genes of the tyrosine degradation cluster (PubMed:22046314). Expression is induced by L-tyrosine. Abolishes the expression of all cluster genes (PubMed:22046314). Impairs growth on L-tyrosine as the sole carbon source and affects homogentisic acid and pyomelanin formation (PubMed:19028908).