Involved in the biosynthesis of the nonproteinogenic amino acid monomer (S)-3,5-dihydroxyphenylglycine (Dpg) responsible of the production of vancomycin and teicoplanin antibiotics. Catalyzes the unusual conversion 3,5-dihydroxyphenylacetyl-CoA (DPA-CoA) to 3,5-dihydroxyphenylglyoxylate. DpgC performed a net four-electron oxidation of the benzylic carbon of DPA-CoA and the hydrolysis of the thioester bond to generate free CoA (PubMed:18004875, PubMed:17507985). DpgC has the ability to process a diverse range of substituted phenylacetyl-CoA substrates (PubMed:18004875). (3,5-dihydroxyphenyl)acetyl-CoA + O2 = 2-(3,5-dihydroxyphenyl)-2-oxoacetate + CoA + H(+) Inhibited by DPA-S-(N-acetylcysteamine). kcat is 10.32 min(-1) for dioxygenase activity with DPA-CoA as substrate (PubMed:18004875). kcat is 0.172 sec(-1) for dioxygenase activity with DPA-CoA as substrate (PubMed:17507985). Homohexamer; dimer of trimers. Belongs to the enoyl-CoA hydratase/isomerase family.