Figure 4. Energetic channeling.

a: The ATP-production module (green) uses the energy of a substrate to convert ADP to ATP, whereas the ATPase module (red) uses the high energy of the phosphoryl bond of ATP to liberate 53 kJ/mol to perform a cellular function. b: As in substrate channeling (see Figure 2b), the association of these two modules results in energetic channeling of ATP from its site of production to its site of consumption without its release into the bulk phase. c: Energetic channeling may also involve ADP and P _i. ADP, adenosine diphosphate; ATP, adenosine 5’-triphosphate; P _i, inorganic phosphate.