Pseudoperoxidase activity of mushroom tyrosinase

Abstract

Under anaerobic conditions, ethyl hydroperoxide functions as a two-electron acceptor in the tyrosinase-catalyzed oxidation of 4- tert-butylcatechol to 4- tert-butyl- o-benzoquinone, apparently by the following mechanism: T−[Cu(II)] 2 + TBC = T−[Cu(I)] 2 + TB− o− BQ + 2H + T−[Cu(I)] 2 + EtOOH + 2H += T−[Cu(II)] 2 + EtOH +H 2O This is a direct demonstration of the pseudoperoxidase activity of tyrosinase. Ethyl hydroperoxide failed to oxidize either oxy- or deoxyhemocyanin.