Principles of Biochemistry, Volume 2 - A. Lehninger 1985

Bioenergetics and Metabolism
Fatty Acid Oxidation in Animal Tissues
During the first stage of fatty acid oxidation, acetyl-CoA and ATP are produced

Thus, we have completed our examination of one turn of the Fatty acid oxidation cycle. The long-chain fatty acyl-CoA entering this cycle loses one molecule of acetyl-CoA and two pairs of hydrogen atoms; upon completion of one turn of the cycle, the fatty acid chain becomes shorter by two carbon atoms. For palmitoyl-CoA (16 carbon atoms), the overall equation for one turn of the oxidation cycle is as follows:

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The Cleavage of one molecule of acetyl-CoA from palmitoyl-CoA yields the CoA ester of myristic acid, whose molecule now contains only 14 carbon atoms. This myristoyl-CoA enters a new oxidation cycle consisting of the same four reactions, which produces yet another molecule of acetyl-CoA and the CoA ester of the homologous 12-carbon lauric acid, lauroyl-CoA. The Complete oxidation of one molecule of palmitoyl-CoA to yield eight molecules of acetyl-CoA requires seven such cycles (Fig. 18-6):

Each FADH2 molecule generated during fatty acid oxidation transfers one pair of electrons to the Respiratory Chain at the ubiquinone level; The transfer of this pair of electrons to oxygen, coupled with Oxidative Phosphorylation, yields two molecules of ATP from ADP and phosphate (Fig. 18-7). Similarly, each NADH molecule formed transfers one pair of electrons to mitochondrial NADH dehydrogenase; As a result of this electron pair transfer to oxygen, three molecules of ATP are synthesized from ADP and phosphate. Thus, for each cleaved molecule of acetyl-CoA, five molecules of ATP are produced (referring to the cycle as it operates in animal Tissues, such as Liver or myocardium). We can therefore write a general equation for The oxidation of palmitoyl-CoA to eight molecules of acetyl-CoA that also accounts for Electron Transport and oxidative phosphorylation:

This overall equation describes The First stage of the fatty acid oxidation process (Fig. 18-5).



Last update: 06/08/2026

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