Laccases as palladium oxidases† †Electronic supplementary information (ESI) available: Experimental procedures, synthesis of catalysts molecules, enzyme activity assay, bleaching experiments, oxygraph traces, oxidation of veratryl alcohol assay, inhibition experiments, electrophoresis. See DOI: 10.1039/c4sc02564d Click here for additional data file.

Complexes 11, 22 and 33 were synthetized according to adapted published protocols. Tris(3,3′,3′′-phosphinidynetris(benzenesulfonato)palladium(0) nonasodium salt nonahydrate] (complex 4), bathophenanthrolinedisulfonic acid disodium salt , bathocuproin disulfonic acid disodium, 2,2′-Biquinoline-4,4′-dicarboxylic acid dipotassium salt, triphenylphosphine-3,3′,3′′-trisulfonic acid trisodium salt ligand, veratryl alcohol, veratryl aldehyde and all chemicals were purchased from Sigma Aldrich and used without further purification. Pd(II) acetate and 1.1 equivalent of ligand were placed in an agate mortar with 2-3 drops of water and finely ground. 3 drops of NaOH 1 M were added to the resulting paste, transferred to a metal-free propylene tube and diluted to 25 mL with water and shaken at 28 °C on a wrist-action shaker for 24 hours. The resulting mixture was then filtered through a nylon membrane (0.2 μm porosity), precipitated with acetone, dried with diethyl ether and used for catalysis. Laccase LAC3 was heterologously expressed in Aspergillus niger and purified according to previously published procedures4.