Fatty acid synthase

Definition

Fatty acid synthase is a multi-enzyme complex that plays a crucial role in the biosynthesis of fatty acids, primarily converting acetyl-CoA and malonyl-CoA into long-chain fatty acids. This process is vital for lipid metabolism, as fatty acids serve as important energy sources and building blocks for various lipids in the body. Fatty acid synthase not only catalyzes the elongation of fatty acid chains but also facilitates the reduction and dehydration steps necessary to create fully saturated fatty acids.

5 Must Know Facts For Your Next Test

1. Fatty acid synthase operates primarily in the cytoplasm of cells and is especially active in liver and adipose tissue.
2. The enzyme complex works through a series of condensation reactions, ultimately producing palmitate, a 16-carbon saturated fatty acid.
3. NADPH is a key cofactor required for the reduction reactions during fatty acid synthesis, providing the necessary reducing power.
4. Regulation of fatty acid synthase is influenced by hormonal signals, such as insulin, which promotes lipogenesis when energy stores are abundant.
5. Deficiencies or malfunctions in fatty acid synthase can lead to metabolic disorders, including issues with lipid metabolism and obesity.

Review Questions

• How does fatty acid synthase contribute to the overall process of lipid metabolism?
  • Fatty acid synthase is a central player in lipid metabolism because it synthesizes long-chain fatty acids from smaller molecules like acetyl-CoA and malonyl-CoA. These fatty acids are essential for forming triglycerides, which store energy, and phospholipids that are crucial for cellular membranes. By facilitating these transformations, fatty acid synthase helps maintain energy balance and cellular structure within the body.
• Discuss the regulatory mechanisms that control fatty acid synthase activity in response to energy availability.
  • Fatty acid synthase activity is closely regulated by hormonal signals such as insulin and glucagon. When energy is plentiful, insulin promotes the expression and activity of fatty acid synthase, stimulating fat storage through lipogenesis. Conversely, during fasting or low-energy states, glucagon can inhibit its activity to redirect resources toward fatty acid oxidation instead of synthesis. This regulation ensures that fatty acids are synthesized primarily when they are needed for energy storage.
• Evaluate the impact of dysfunctional fatty acid synthase on human health and its connection to metabolic diseases.
  • Dysfunction of fatty acid synthase can have significant repercussions on human health by disrupting normal lipid metabolism. For example, if fatty acid synthase is overactive, it may lead to excessive fat accumulation and contribute to obesity, insulin resistance, and non-alcoholic fatty liver disease. Conversely, underactivity could impair lipid synthesis, leading to deficits in essential fatty acids and potential issues with membrane integrity. Understanding these connections highlights the importance of regulating this enzyme for metabolic health.

Related terms

Acetyl-CoA: A central metabolite that serves as a building block for fatty acid synthesis and is generated from carbohydrates, fats, and proteins.

Malonyl-CoA: An important intermediate in fatty acid synthesis formed from acetyl-CoA by the action of the enzyme acetyl-CoA carboxylase.

Lipid Metabolism: The biochemical process involving the synthesis and degradation of lipids in cells, which includes the pathways for fatty acid synthesis and oxidation.