Energy transduction by respiratory metallo-enzymes: From molecular mechanism to cell physiology

Membrane integrated respiratory metallo-enzymes occur in all three domains of life and perform the bioenergetic reactions sustaining the living state of the cell. To this end these enzymes catalyze redox chemical reactions that require tightly controlled electron transfer, proton binding and proton translocation events. The great quantity of structural and kinetic studies performed in the last two decades has provided the molecular detail needed for a basic understanding as to how respiratory enzymes convert redox free energy into a proton-motive force. In this review these recent developments are discussed within the framework of Peter Mitchell's Chemiosmotic Hypothesis that is by now a Theory.

► Respiratory metallo-enzymes perform the bioenergetic reactions that sustain life.
► The background for bioenergetics is provided by Mitchell's Chemiosmotic Theory.
► Pathways of electron transfer and proton translocation in various enzymes are reviewed.