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Oxidative phosphorylation• Chemiosmotic
coupling hypothesis• Proton motive force• Production of ATP• NADH from
Glycolysis• Total ATP • Transport of ATP • Rates of Respiration
Chemiosmotic coupling hypothesis
• Peter Mitchell • Movement of H+
across inner membrane produces gradient
Proton motive force
• Two components – membrane potential – pH gradient
• Calculate gradient using equation – pH gradient 1.4 units
in liver and E. coli• 12 H+ pumped out/
pair of electrons
Proton motive force
ATP synthase in inner membrane
• Two components • F1 stalk, matrix of
mitochondria
• Fo in membrane
F1 stalk, matrix of mitochondria
• Α3, β3, γ,δ,ε subunits: β interacts with γ.• T(tight) = binds ATP• L (loose) = ADP & Pi• O (open) = bound or release nucleotide• Rotation of γ subunit due to movement of protons
through Fo
Fo in membrane
• Fo hydrophobic, proton channel• a subunit and c rings (10-14 rings)• H+ enters cytosolic channel neutralize aspartic acid• c ring rotates• H+ leaves matrix channel, aspartic acid charged• repeat
Production of ATP
• 10 protons/NADH pumped out
• 2.5 ATP/NADH • 1.5 ATP/FADH • How much ATP? • Pyruvate to Acetyl
CoA • TCA cycle
NADH from GlycolysisMalate-aspartate shuttle Glycerol 3-P shuttle
Total ATP
• Glycolysis and TCA cycle
• Efficiency compared to just glycolysis
Transporters
• ATP/ADP exchange • Pi/OH- exchange
Rates of Respiration
• O2 consumption versus time
• Addition of ADP needed
• calculate P/O ratio of different compounds
Respiration rates
Respiration--Uncouplers
• Uncouplers and their effect
• DNP • valinomycin• gramicidin • Brown adipose tissue• Thermogenin (UCP-
1), dimer
Coupling of electron transfer to ATP synthesis