Acyl-coa dehydrogenase

Definition

Acyl-CoA dehydrogenase is an enzyme that catalyzes the first step in the β-oxidation of fatty acids, which involves the oxidation of acyl-CoA to trans-enoyl-CoA. This enzyme plays a crucial role in lipid metabolism by enabling the breakdown of fatty acids into acetyl-CoA units that can enter the citric acid cycle for energy production.

5 Must Know Facts For Your Next Test

1. Acyl-CoA dehydrogenase is specific to different lengths of fatty acids, with distinct isoforms for short, medium, and long-chain fatty acids.
2. The reaction catalyzed by this enzyme produces FADH2, which is then utilized in the electron transport chain to generate ATP.
3. Deficiencies in acyl-CoA dehydrogenase can lead to metabolic disorders such as Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD), which affects the body's ability to metabolize fatty acids.
4. The enzyme is located in the mitochondrial matrix, where fatty acid oxidation primarily occurs.
5. Acyl-CoA dehydrogenase is essential for maintaining energy homeostasis during periods of fasting or prolonged exercise when carbohydrates are limited.

Review Questions

• How does acyl-coa dehydrogenase contribute to the process of β-oxidation, and what is its specific role?
  • Acyl-CoA dehydrogenase initiates β-oxidation by catalyzing the conversion of acyl-CoA into trans-enoyl-CoA. This first step involves the removal of two hydrogen atoms from acyl-CoA and transferring them to FAD, forming FADH2. This reaction is critical because it sets up the subsequent steps of β-oxidation, ultimately leading to the production of acetyl-CoA that can enter the citric acid cycle for energy generation.
• Discuss the implications of acyl-coa dehydrogenase deficiencies on human health and metabolism.
  • Deficiencies in acyl-coa dehydrogenase can lead to various metabolic disorders, particularly Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD). Individuals with this condition cannot effectively break down medium-chain fatty acids during periods of fasting or stress, leading to toxic accumulation of fatty acids and decreased energy production. Symptoms can include hypoglycemia, lethargy, and potentially serious complications if not managed properly. Understanding this enzyme's function highlights its importance in lipid metabolism and overall energy balance.
• Evaluate how changes in acyl-coa dehydrogenase activity might affect overall lipid metabolism and energy production during different physiological states.
  • Changes in acyl-coa dehydrogenase activity can significantly impact lipid metabolism and energy production. For instance, during fasting or exercise when carbohydrate reserves are low, increased activity of this enzyme allows for enhanced β-oxidation of fatty acids, ensuring a steady supply of acetyl-CoA for energy production. Conversely, reduced activity could impair fatty acid breakdown, leading to a reliance on less efficient energy sources such as glucose. This could result in metabolic inflexibility and potentially contribute to conditions like obesity or insulin resistance if not balanced appropriately.

Related terms

β-oxidation: The metabolic process by which fatty acids are broken down in the mitochondria to produce acetyl-CoA, NADH, and FADH2.

fatty acyl-CoA: A molecule formed by the attachment of Coenzyme A to a fatty acid, which is necessary for its transport into the mitochondria for β-oxidation.

FAD (Flavin adenine dinucleotide): A redox cofactor involved in several important reactions in metabolism, acting as an electron carrier in the dehydrogenation reactions catalyzed by acyl-CoA dehydrogenase.