What is produced during the conversion of alpha-ketoglutarate to oxaloacetate in the citric acid cycle?

The conversion of alpha-ketoglutarate to oxaloacetate in the citric acid cycle, also referred to as the Krebs cycle or TCA cycle, does not actually occur directly. Instead, the correct pathway involves the conversion of alpha-ketoglutarate to succinyl-CoA, which produces one molecule of NADH and releases carbon dioxide. Subsequently, succinyl-CoA is converted to succinate, during which another NADH is produced and eventually leads to the regeneration of oxaloacetate.

To clarify, the complete cycle involves multiple steps and several transformations of the intermediates, ultimately leading to the regeneration of oxaloacetate. The overall production during the complete conversion processes which includes alpha-ketoglutarate through to oxaloacetate would result in a net yield of three NADH, one FADH2, and one GTP or ATP per turn of the cycle. However, the specifics of the energy carriers produced depend on the accumulated transformations and are rather specific about which steps yield each type of high-energy molecule.

In this context, the production of high-energy electron carriers, such as NADH and FADH2, is critical for cellular respiration, as these molecules enter the electron transport chain