3-hydroxyacyl-coa dehydrogenase

Definition

3-hydroxyacyl-CoA dehydrogenase is an important enzyme that plays a crucial role in the metabolism of fatty acids, specifically in the β-oxidation pathway. This enzyme catalyzes the conversion of 3-hydroxyacyl-CoA to 3-ketoacyl-CoA, facilitating the breakdown of fatty acids into acetyl-CoA units for energy production. Its activity is vital for maintaining energy homeostasis during periods of fasting or increased energy demand.

5 Must Know Facts For Your Next Test

1. 3-hydroxyacyl-CoA dehydrogenase is part of a multi-enzyme complex involved in the mitochondrial β-oxidation of fatty acids, ensuring efficient energy production.
2. The enzyme requires NAD+ as a cofactor to facilitate the oxidation of 3-hydroxyacyl-CoA to 3-ketoacyl-CoA, generating NADH in the process.
3. Deficiencies in this enzyme can lead to metabolic disorders such as fatty acid oxidation defects, resulting in hypoglycemia and muscle weakness during periods of fasting.
4. This enzyme is highly regulated and its activity can be influenced by factors such as substrate availability and hormonal signaling, particularly insulin and glucagon.
5. 3-hydroxyacyl-CoA dehydrogenase exists in various isoforms, which can differ in tissue distribution and specific substrate preferences.

Review Questions

• How does 3-hydroxyacyl-CoA dehydrogenase contribute to energy production through fatty acid metabolism?
  • 3-hydroxyacyl-CoA dehydrogenase plays a key role in the β-oxidation pathway by converting 3-hydroxyacyl-CoA to 3-ketoacyl-CoA. This reaction not only facilitates the breakdown of fatty acids into acetyl-CoA units but also generates NADH, which can be used in the electron transport chain to produce ATP. Therefore, this enzyme is essential for maintaining energy levels, especially during periods when carbohydrate sources are limited.
• Discuss the implications of enzyme deficiencies related to 3-hydroxyacyl-CoA dehydrogenase in terms of metabolic health.
  • Deficiencies in 3-hydroxyacyl-CoA dehydrogenase can lead to severe metabolic disorders characterized by impaired fatty acid oxidation. Patients may experience symptoms such as hypoglycemia due to an inability to mobilize fatty acids for energy during fasting states. Furthermore, muscle weakness may occur due to inadequate energy supply during exercise or stress. These conditions highlight the enzyme's critical role in metabolic health and underscore the importance of proper fatty acid metabolism.
• Evaluate the regulatory mechanisms that control the activity of 3-hydroxyacyl-CoA dehydrogenase and their significance in metabolic balance.
  • The activity of 3-hydroxyacyl-CoA dehydrogenase is tightly regulated by factors like substrate availability and hormonal signals such as insulin and glucagon. Insulin promotes fatty acid synthesis while inhibiting β-oxidation, leading to decreased activity of this enzyme. Conversely, glucagon stimulates fat breakdown during fasting, enhancing enzyme activity. This regulatory balance is vital for ensuring that energy production matches physiological needs and helps maintain overall metabolic homeostasis.

Related terms

β-oxidation:

A metabolic process that breaks down fatty acids to generate acetyl-CoA, which can be used in the Krebs cycle for energy production.

Acetyl-CoA: A central metabolic intermediate that serves as a key substrate for the Krebs cycle and is generated from the breakdown of carbohydrates, fats, and proteins.

Carnitine: A molecule that transports long-chain fatty acids into the mitochondria, where they undergo β-oxidation, playing a critical role in fatty acid metabolism.