A B C glucose -> 2 pyruvate -> 2 acetylCoA -> Kreb's cycle A generates 2 ATP 2 NADH (cytoplasmic) B generates 2 x 1NADH = 2 NADH C generates 2 x (1 ATP, 1 FADH, 3 NADH) = 2 ATP 6 NADH 2 FADH2 Total 4 ATP 10 NADH 2 FADH2
For the mitochondria, "textbook" stoichiometries are:
ATP/2e ratio for NADH oxidation = 2.5
ATP/2e ratio for succinate oxidation (via FADH2) = 1.5
These are based on the following assumptions for H+/ATP and H+/2e ratios:
Complex I span 4H+/2e Complex II span 0H+/2e Complex III span 2H+/2e ( + 2 scalar H+/2e) Complex IV span 4H+/2e ( - 2 scalar H+/2e) ATP-synthase 3H+/ATP Transport of phosphate, and exchange of ADP/ATP- 1H+/ATP Total for ATP synthesis 4H+/ATP From this: NADH -> O2 10 H+/2e 10/4 = 2.5 ATP/NADH Succinate -> O2 6 H+/2e 6/4 = 1.5 ATP/FADH2
The main areas of uncertainty are the stoichiometry for the Complex I span, and the H+/ATP stoichiometry, which may not be integer. However, the textbook values are likely to be pretty close to the real values, and within the range of experimental uncertainty.
The yield of ATP from the cytoplasmic NADH depends on the pathway by which the reducing equivalents reach the respiratory chain, which is tissue dependent. If via the glutamate/aspartate shuttle, the yield is the same as the mitochondrial yield, minus 1 H+/NADH (or 0.25 ATP/NADH); if via dihydroxyacetone phosphate, the Complex I span is by-passed, losing 1 ATP/NADH.