key term - Carnitine palmitoyltransferase ii

Definition

Carnitine palmitoyltransferase II (CPT II) is an enzyme located in the mitochondrial inner membrane that plays a crucial role in the metabolism of long-chain fatty acids. It catalyzes the conversion of acylcarnitines back to acyl-CoA, facilitating the entry of fatty acids into the mitochondrial matrix for energy production through beta-oxidation. This process is essential for the degradation of fatty acids and the generation of ketone bodies during periods of fasting or prolonged exercise.

5 Must Know Facts For Your Next Test

1. CPT II is essential for converting acylcarnitines back to acyl-CoA, enabling the utilization of long-chain fatty acids for energy during fasting or strenuous activity.
2. Deficiencies in CPT II can lead to metabolic disorders, causing symptoms like muscle pain and weakness during exercise due to impaired fatty acid oxidation.
3. CPT II operates in conjunction with CPT I, which facilitates the transport of fatty acids into mitochondria by converting them to acylcarnitines.
4. The regulation of CPT II activity is influenced by the availability of carnitine and the energy status of the cell, ensuring efficient fatty acid metabolism.
5. CPT II plays a significant role in ketogenesis, particularly during prolonged fasting or low-carbohydrate diets, where increased fat utilization is necessary.

Review Questions

• How does carnitine palmitoyltransferase II contribute to the metabolism of long-chain fatty acids?
  • Carnitine palmitoyltransferase II (CPT II) is crucial for metabolizing long-chain fatty acids as it converts acylcarnitines back into acyl-CoA within the mitochondria. This conversion allows fatty acids to undergo beta-oxidation, where they are broken down into acetyl-CoA for energy production. Without CPT II's function, long-chain fatty acids would accumulate outside the mitochondria, impairing energy generation during fasting or intense exercise.
• Discuss the consequences of a deficiency in carnitine palmitoyltransferase II and its effects on overall metabolism.
  • A deficiency in carnitine palmitoyltransferase II can lead to significant metabolic issues, particularly affecting muscle metabolism. Individuals with CPT II deficiency may experience muscle pain and weakness during exercise due to an inability to effectively oxidize long-chain fatty acids. This condition highlights the importance of CPT II in maintaining energy levels during physical activity, as it prevents the normal degradation of fats into usable energy.
• Evaluate the role of carnitine palmitoyltransferase II in ketogenesis and its implications for dietary practices like low-carbohydrate diets.
  • Carnitine palmitoyltransferase II is vital in ketogenesis, especially when carbohydrates are limited. During periods of fasting or low-carbohydrate diets, CPT II enables the breakdown of stored fats into acetyl-CoA, which can then be converted into ketone bodies for energy. This process is essential not only for sustaining energy levels but also for supporting brain function during metabolic shifts away from glucose utilization. Thus, understanding CPT II's function helps explain how dietary choices impact fat metabolism and energy homeostasis.

Related terms

Fatty acid oxidation: The metabolic process through which fatty acids are broken down in the mitochondria to generate acetyl-CoA, which can enter the citric acid cycle for energy production.

Carnitine: A compound that transports long-chain fatty acids across the mitochondrial membrane, where they can be oxidized for energy.

Beta-oxidation: A metabolic pathway that involves the breakdown of fatty acids into acetyl-CoA units, which are then utilized in various metabolic processes including energy production.