Oxygen Binding, Activation, and Reduction to Water by Copper Proteins

Abstract

Copper active sites play a major role in biological and abiological dioxygen activation. Oxygen intermediates have been studied in detail for the proteins and enzymes involved in reversible O₂ binding (hemocyanin), activation (tyrosinase), and four-electron reduction to water (multicopper oxidases). These oxygen intermediates exhibit unique spectroscopic features indicative of new geometric and electronic structures involved in oxygen activation. The spectroscopic and quantum-mechanical study of these intermediates has defined geometric- and electronic-structure/function correlations, and developed detailed reaction coordinates for the reversible binding of O₂, hydroxylation, and H-atom abstraction from different substrates, and the reductive cleavage of the O−O bond in the formation water.