Evidence for H-bonding interactions to the µ-η2:η2-peroxide of oxy-tyrosinase that activate its coupled binuclear copper site.

The factors that control the diverse reactivity of the µ-η2:η2-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-η2:η2-peroxide of oxy-tyrosinase, and define their effects on the Cu(II)2O2 electronic structure and O2 activation.