The electrochemical properties of the highly diverse terminal oxidases from different organisms

Terminal oxidases are critical for aerobic respiratory chains of prokaryotes and eukaryotes, responsible for the final step in the electron transport chain. These enzymes catalyze the transfer of electrons from reduced electron carriers (such as cytochrome c or quinols) to the terminal electron acceptor, molecular oxygen (O₂), thereby reducing it to water. They play a pivotal role in aerobic respiration and energy metabolism, adapting to diverse environmental and physiological needs across different organisms. This review summarizes the electrochemical properties of terminal oxidases from different organisms and reveals their high degree of adaptivity with redox potentials spanning more than 500 mV. The electrocatalytic response in direct electrochemical approaches is described giving insight into the rich and complex electron and proton transfer catalysed by these essential enzymes.