Which enzyme catalyzes the conversion of isocitrate to alpha-ketoglutarate?

The enzyme that catalyzes the conversion of isocitrate to alpha-ketoglutarate is isocitrate dehydrogenase. This reaction involves the oxidative decarboxylation of isocitrate, resulting in the release of carbon dioxide and the production of NADH from NAD+. This step is crucial in the citric acid cycle, as it not only progresses the cycle forward but also links the metabolism of carbohydrates and fats to the cell's energy production.

Isocitrate dehydrogenase plays a pivotal role by facilitating the transformation of a six-carbon compound (isocitrate) into a five-carbon compound (alpha-ketoglutarate), which is essential for maintaining the continuity of the citric acid cycle. The enzyme is sensitive to various regulatory mechanisms and can be impacted by the availability of substrates and products, contributing to the overall regulation of cellular respiration.

The other enzymes listed serve different functions within the metabolism pathway. Pyruvate dehydrogenase is involved in the conversion of pyruvate to acetyl-CoA, citrate synthase catalyzes the formation of citrate from acetyl-CoA and oxaloacetate, and fumarase focuses on the hydration of fumarate to malate. Each of these enzymes performs