A soluble enzyme fraction from Phanerochaete chrysosporium catalyzed the oxidative decarboxylation of vanillic acid to methoxy-p-hydroquinone. The enzyme, partially purified by ammonium sulfate precipitation, required NADPH and molecular oxygen for activity. NADH was not effective. Optimal activity was displayed between pH 7.5-8.5. Neither EDTA, KCN, NaN3, nor o-phenanthroline (5 mM) were inhibitory. The enzyme was inducible with maximal activity displayed after incubation of previously grown cells with 0.1% vanillate for 30h. © 1979 Springer-Verlag.