In the citric acid cycle, oxaloacetate (a 4 carbon molecule) is combined with acetyl CoA (a 2 carbon molecule) to generate the 6 carbon molecule citric acid. Acetyl CoA is generated from the oxidation of pyruvate (which also generates CO2), and from the oxidation of fatty acids. In the eigth and last step of the citric acid cycle, oxaloacetate is regenerated from malate by malate dehydrogenase so it can once again combine with acetyl CoA and keep the cycle going .
- ↑ Alberts et al. Molecular Biology of the Cell (2008) 5th edition, Garland Science