What type of reaction involves the conversion of isocitrate to alpha-ketoglutarate?

The conversion of isocitrate to alpha-ketoglutarate is a decarboxylation reaction. In this step of the citric acid cycle, isocitrate undergoes a structural transformation where a carboxyl group is removed and released as carbon dioxide (CO₂). This process reduces the carbon skeleton of the molecule, resulting in the formation of alpha-ketoglutarate.

Additionally, this reaction is also coupled with the reduction of NAD⁺ to NADH, indicating that it involves both decarboxylation and oxidation processes, but the defining feature of this transformation is the release of the carboxyl group, which characterizes it as a decarboxylation reaction. The removal of CO₂ is crucial, as it transforms the six-carbon isocitrate into a five-carbon alpha-ketoglutarate. Understanding this reaction is fundamental because it links the citric acid cycle to the broader metabolic pathways of cellular respiration.