Reduction of dioxygen by enzymes containing copper.

The reduction of dioxygen is a key step in many important biological processes including respiration and ligand oxidation. Enzymes containing either iron or copper or, indeed, both elements are often involved in this process, yet the catalytic mechanisms employed are not fully understood at the current time despite intensive biochemical, spectroscopic and structural studies. The aim of this article is to highlight the current structural knowledge regarding the process of dioxygen reduction using examples of copper-containing enzymes.