For typical values of these terms ph 10 and ψ 150 mv

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For typical values of these terms ( pH = 1.0, and ∆Ψ = -150 mV at 37°C) G = -5.9 kJ/mol - 14.5 kJ/mol G = -20.4 kJ/mol Thus, both features of the proton gradient contribute to the energy available to synthesize ATP. The "ATP synthase motor" (FoF1 ATPase) converts the free energy of the proton gradient to chemical energy in the form of ATP. The Fo Complex Membrane-spanning, multiprotein complex (13 subunits: a, b 2 , and c 10 ). Responsible for coupling the movement of three protons to 120° rotations of the c- subunit ring and the γ subunit of the F1 complex. The antibiotic, oligomycin B, binds to Fo and prevents H + transport. Hence the name, F o . The F1 Complex Five different subunits: α 3 β 3 γδε Attached to Fo, it protrudes into the mitochondrial matrix. The β subunits are asymmetric due to their interactions with the Fo. 1. One β subunit has very low affinity for both ADP and ATP. 2. One β subunit has high affinity for ADP and P i . 3. One β subunit has high affinity for ATP. The γ subunit is the rotating shaft at the center of the α 3 β 3 disk. How the motor works (See the tutorial linked at the top of this page.)
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4 Every time three protons are pumped, the F1 γ subunit rotates 120°. The actual synthesis (formation of the bond between ADP and P i is catalyzed by conformational changes of the enzyme that occur as a consequence of the rotation. The key point is that the rotation changes the β subunit that contains ADP + P i to a new conformation. In this new conformation the β subunit would rather bind ATP, and thus catalyzes the formation of a ATP from the bound ADP and P i . The newly-formed ATP is released with the transport of three additional protons.
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