key term - Fatty acid synthase

Definition

Fatty acid synthase is a multi-enzyme complex that plays a crucial role in the biosynthesis of fatty acids, primarily in the liver and adipose tissue. This enzyme catalyzes the sequential addition of two-carbon units derived from acetyl-CoA and malonyl-CoA to form long-chain fatty acids, which are essential for various biological functions including energy storage, membrane structure, and signaling molecules.

5 Must Know Facts For Your Next Test

1. Fatty acid synthase operates through a series of reactions that involve the reduction, dehydration, and condensation of substrates to build long-chain fatty acids.
2. This enzyme is regulated by nutritional states; it is typically active when carbohydrates are abundant, promoting fatty acid synthesis for energy storage.
3. In humans, fatty acid synthase produces primarily palmitate (C16:0), but can also elongate and desaturate fatty acids to form various types of lipids.
4. The enzyme exists as a dimer or multimer in mammals, meaning it can form complexes with multiple copies of its components to enhance its efficiency.
5. Defects in fatty acid synthase or its regulation can lead to metabolic disorders, obesity, and other health issues related to lipid imbalances.

Review Questions

• How does fatty acid synthase contribute to energy storage in the body?
  • Fatty acid synthase synthesizes long-chain fatty acids from acetyl-CoA and malonyl-CoA, which are then converted into triglycerides for energy storage. When carbohydrates are plentiful, this process becomes more active, allowing excess energy to be stored as fat. This stored fat can later be mobilized when energy is needed, highlighting the enzyme's key role in managing energy balance.
• What are the regulatory mechanisms that control the activity of fatty acid synthase in response to dietary conditions?
  • Fatty acid synthase activity is regulated by various factors including insulin levels, nutrient availability, and hormonal signals. For instance, high carbohydrate intake increases insulin secretion, promoting the activity of fatty acid synthase. Conversely, during fasting or low-carbohydrate conditions, glucagon inhibits its activity to prevent unnecessary fatty acid synthesis when energy is scarce.
• Evaluate the impact of fatty acid synthase on overall lipid metabolism and its potential link to metabolic diseases.
  • Fatty acid synthase plays a pivotal role in lipid metabolism by facilitating the conversion of excess carbohydrates into fatty acids for storage. Dysregulation of this enzyme can lead to excessive fat accumulation and contribute to metabolic diseases such as obesity, type 2 diabetes, and cardiovascular disorders. Understanding how fatty acid synthase operates can provide insights into therapeutic targets for these conditions and highlight its importance in maintaining metabolic health.

Related terms

Acetyl-CoA: A central metabolite in energy metabolism that serves as a building block for the synthesis of fatty acids and other biomolecules.

Malonyl-CoA:

A key intermediate in fatty acid synthesis that provides the two-carbon units for the elongation process in fatty acid synthase.

Lipid metabolism: The complex set of biochemical processes responsible for the synthesis and degradation of lipids in cells, including fatty acid synthesis and degradation.