Which step directly follows the formation of citrate in the citric acid cycle?

Which step directly follows the formation of citrate in the citric acid cycle?

• A. Aconitase reaction
• B. Isocitrate formation
• C. Pyrvate decarboxylation
• D. Fumarate formation

Answer: (A)

The step that directly follows the formation of citrate in the citric acid cycle is the aconitase reaction. After citrate is formed from acetyl-CoA and oxaloacetate, it undergoes a rearrangement catalyzed by the enzyme aconitase. This reaction converts citrate into isocitrate through an intermediate known as cis-aconitate. The aconitase reaction is crucial as it prepares the substrate for subsequent transformations in the cycle, leading eventually to the production of energy-dense molecules like NADH and FADH2. This role of aconitase emphasizes the importance of specific enzyme-catalyzed conversions in metabolic pathways and showcases the cyclic nature of the citric acid cycle, wherein each compound is systematically transformed to harvest energy efficiently.

The step that directly follows the formation of citrate in the citric acid cycle is the aconitase reaction. After citrate is formed from acetyl-CoA and oxaloacetate, it undergoes a rearrangement catalyzed by the enzyme aconitase. This reaction converts citrate into isocitrate through an intermediate known as cis-aconitate. The aconitase reaction is crucial as it prepares the substrate for subsequent transformations in the cycle, leading eventually to the production of energy-dense molecules like NADH and FADH2. This role of aconitase emphasizes the importance of specific enzyme-catalyzed conversions in metabolic pathways and showcases the cyclic nature of the citric acid cycle, wherein each compound is systematically transformed to harvest energy efficiently.