Proton-motive ATP synthase and energy transfer in the cell

The H+-ATP synthase of mitochondria is the key enzyme of energy metabolism in eukaryotic cells (Senior, 1988). It is responsible for the synthesis of ATP supported by respiration, which covers, under normal conditions, more than 80% of the energy demand of mammalian cells. An adult man with a daily energy demand of some 3000 kcal turns over some 400 mol of ATP (200 kg). The brain is the organ with the highest demand for aerobic ATP, accounting, with only 2% of the body weight, for 20% of total oxygen consumption at rest (Erecinksa and Silver, 1989).