Energy Yield
The ATP yield for every oxidation cycle is 14 ATP (according to the P/O ratio), broken down as follows:
Source | ATP | Total |
1 FADH2 | x 1.5 ATP | = 1.5 ATP (some sources say 2 ATP) |
1 NADH | x 2.5 ATP | = 2.5 ATP (some sources say 3 ATP) |
1 acetyl CoA | x 10 ATP | = 10 ATP (some sources say 12 ATP) |
TOTAL | = 14 ATP |
For an even-numbered saturated fat (C2n), n - 1 oxidations are necessary, and the final process yields an additional acetyl CoA. In addition, two equivalents of ATP are lost during the activation of the fatty acid. Therefore, the total ATP yield can be stated as:
- (n - 1) * 14 + 10 - 2 = total ATP
For instance, the ATP yield of palmitate (C16, n = 8) is:
- (8 - 1) * 14 + 10 - 2 = 106 ATP
Represented in table form:
Source | ATP | Total |
7 FADH2 | x 1.5 ATP | = 10.5 ATP |
7 NADH | x 2.5 ATP | = 17.5 ATP |
8 acetyl CoA | x 10 ATP | = 80 ATP |
Activation | = -2 ATP | |
NET | = 106 ATP |
For sources that use the larger ATP production numbers described above, the total would be 129 ATP ={(8-1)*17+12-2} equivalents per palmitate.
Beta-oxidation of unsaturated fatty acids changes the ATP yield due to the requirement of two possible additional enzymes.
Read more about this topic: Beta Oxidation
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