The ubiquitous copper enzyme tyrosinase catalyzes the ohydroxylation of monophenols to catechols along with subsequent two-electron oxidation to o-quinones.[1–3] Its physiological function is to initiate melanin synthesis by converting tyrosine to dopaquinone, which spontaneously polymerizes in a non-enzymatic reaction cascade.[4, 5] Various recent crystal structures of different tyrosinases revealed a binuclear copper type 3 active site, with each ...