Involved in the biosynthesis of paerucumarin, a cyclized isocyano derivative of tyrosine (PubMed:18689486, PubMed:18824174). Catalyzes the 2-oxoglutarate-dependent oxidation of tyrosine isonitrile (PubMed:25866990). (2S)-3-(4-hydroxyphenyl)-2-isocyanopropanoate + 2-oxoglutarate + O2 = (2E)-3-(4-hydroxyphenyl)-2-isocyanoprop-2-enoate + CO2 + H2O + succinate Binds 1 Fe(2+) per subunit. kcat is 2.3 sec(-1). Homotrimer in solution. Disruption of the gene maintains the ability of the strain to produce the pyoverdine siderophore (PubMed:18824174). Deletion mutant is more sensitive to chloramphenicol and ciprofloxacin in comparison with its parent strain. This sensitivity is probably due to transcriptional repression of mexT and mexEF-oprN genes. Exogenous addition of paerucumarin resumes the expression of mexT and mexEF-oprN genes as well as resistance against chloramphenicol and ciprofloxacin (PubMed:32941967). Belongs to the TfdA dioxygenase family.