Evidence for H-bonding interactions to the μ-η 2 :η 2 -peroxide of oxy-tyrosinase that activate its coupled binuclear copper site.

The factors that control the diverse reactivity of the μ-η 2 :η 2 -peroxo dicopper(II) oxy-intermediates in the coupled binuclear copper proteins remain elusive. Here, spectroscopic and computational methods reveal H-bonding interactions between active-site waters and the μ-η 2 :η 2 -peroxide of oxy-tyrosinase, and define their effects on the Cu(II) 2 O 2 electronic structure and O 2 activation.