How anaerobic respiration is differentiated from fermentation?
We proposed long ago the following sequence as one of the main pathways in the evolution of energy-yielding metabolism: fermentationnitrate fermentationnitrate respirationoxygen respiration. In the present report our concept is presented in a more general form: (1) fermentation (2) fermentation with H2 release(3) inorganic types of fermentation(4) anaerobic respirations (5) oxygen respiration, based upon recent biological and physical information. The energy-yielding efficiency increased gradually together with the evolution. (2) is characterized by the participation of ferredoxin, (3) by the establishment of electron transfer chain, and (4) by the participation of cytochrome and oxidative phosphorylation. The close relationship between the primary structure of ferredoxins of anaerobic bacteria and that of a cytochrome (cytochromec 3) was demonstrated. It reveals that the transition from inorganic types of fermentation to anaerobic respirations was direct and accompanied by the transit
