Peroxidase and H2O2 oxidized 4-methoxy-2,6-dimethylaniline to a crystalline purple compound which by degradation and unambiguous synthesis was proved to be 2, 6-dimethylbenzoquinone-4-(4[image]-methoxy-2[image], 6[image]-dimethyl) anil. Ammonia and methanol were also produced during the oxidation. Hypothetical intermediate compounds were postulated to explain the reaction. It appeared that amines contain-ing powerful electron-attracting groups were not readily oxidized by the peroxidase system.