Enzyme-Oxaloacetate Complex

Definition

The enzyme-oxaloacetate complex is a key intermediate in the citric acid cycle, also known as the Krebs cycle. It is formed when the enzyme citrate synthase catalyzes the condensation of acetyl-CoA and oxaloacetate to produce citrate, the first step in the cyclic pathway of cellular respiration.

5 Must Know Facts For Your Next Test

1. The enzyme-oxaloacetate complex is an essential intermediate in the citric acid cycle, which is the central metabolic pathway for energy production in aerobic organisms.
2. Citrate synthase is the rate-limiting enzyme that catalyzes the condensation of acetyl-CoA and oxaloacetate to form the enzyme-oxaloacetate complex, initiating the citric acid cycle.
3. The enzyme-oxaloacetate complex is a transient intermediate that is quickly converted to citrate, releasing the oxaloacetate to be recycled in the cycle.
4. The formation of the enzyme-oxaloacetate complex is a thermodynamically favorable reaction that drives the citric acid cycle forward, making it an important control point in cellular respiration.
5. Disruption or inhibition of the enzyme-oxaloacetate complex can lead to metabolic disorders and impaired energy production in cells.

Review Questions

• Describe the role of the enzyme-oxaloacetate complex in the citric acid cycle.
  • The enzyme-oxaloacetate complex is a crucial intermediate in the citric acid cycle, formed when the enzyme citrate synthase catalyzes the condensation of acetyl-CoA and oxaloacetate. This reaction initiates the cyclic pathway of the citric acid cycle, allowing for the oxidation of acetyl-CoA and the reduction of coenzymes that feed into the electron transport chain. The formation of the enzyme-oxaloacetate complex is a thermodynamically favorable step that drives the citric acid cycle forward, making it an important control point in cellular respiration and energy production.
• Explain how the enzyme-oxaloacetate complex is related to the function of citrate synthase.
  • Citrate synthase is the enzyme responsible for catalyzing the formation of the enzyme-oxaloacetate complex. This enzyme-catalyzed reaction involves the condensation of acetyl-CoA and oxaloacetate to produce citrate, the first step in the citric acid cycle. The enzyme-oxaloacetate complex is a transient intermediate that is quickly converted to citrate, with the oxaloacetate being recycled back into the cycle. Citrate synthase is considered the rate-limiting enzyme in the citric acid cycle, making the formation of the enzyme-oxaloacetate complex a crucial control point in cellular respiration and energy production.
• Analyze the importance of the enzyme-oxaloacetate complex in the context of how enzymes work, as described in section 26.11.
  • The enzyme-oxaloacetate complex is a prime example of how enzymes work to facilitate and regulate metabolic pathways, as discussed in section 26.11. The formation of this complex is catalyzed by the enzyme citrate synthase, which lowers the activation energy required for the condensation of acetyl-CoA and oxaloacetate. This enzymatic reaction is thermodynamically favorable and drives the citric acid cycle forward, making the enzyme-oxaloacetate complex a critical control point in cellular respiration and energy production. The transient nature of the complex, as it is quickly converted to citrate, also demonstrates how enzymes can provide a platform for the efficient progression of metabolic reactions. Understanding the role of the enzyme-oxaloacetate complex within the broader context of enzyme function and the citric acid cycle is essential for comprehending the mechanisms of cellular energy metabolism.

Related terms

Citrate Synthase:

The enzyme that catalyzes the condensation of acetyl-CoA and oxaloacetate to form citrate, the first step in the citric acid cycle.

Acetyl-CoA:

The acetyl group carrier molecule that enters the citric acid cycle and combines with oxaloacetate to form citrate.

Citric Acid Cycle:

The cyclic pathway of cellular respiration that oxidizes acetyl-CoA to carbon dioxide and reduces coenzymes that feed into the electron transport chain.