AUTOXIDATION OF 4-METHYLCATECHOL - A MODEL FOR THE STUDY OF THE BIOSYNTHESIS OF COPPER AMINE OXIDASES QUINONOID COFACTOR

The autoxidation of 4-methylcatechol under quasi-physiological conditi ons, leading to 2-hyddroxy-5-1,4-benzoquinone, was investigated. The e ffects of pH and metal ions were examined. An electrophilic attack of dioxygen to the 4-methylcatechol monoanion to form a transient peroxo species is proposed. It was concluded that such a non-enzymic conversi on is likely for this model compound and for its physiological counter part, a specific tyrosyl residue incorporated in the protein chain al the active site of copper amine oxidases. (C) 1995 Academic Press, Inc .