medium-chain fatty-acyl-CoA metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving medium-chain fatty-acyl-CoAs, any derivative of coenzyme A in which the sulfhydryl group is in a thioester linkage with a long-chain fatty-acyl group. A medium-chain fatty acid has an aliphatic tail containing 6 to 12 carbons. [GOC:pm]

Medium-chain fatty-acyl-CoA metabolic process involves the breakdown and utilization of medium-chain fatty acids (MCFAs), which are saturated fatty acids containing 6 to 12 carbon atoms. This process occurs primarily in the mitochondria, where MCFAs undergo a series of enzymatic reactions to produce energy in the form of ATP.

The process begins with the activation of MCFAs by attaching them to coenzyme A (CoA) to form medium-chain fatty-acyl-CoA. This activation step is catalyzed by the enzyme acyl-CoA synthetase.

Next, the activated MCFAs are transported into the mitochondrial matrix through the carnitine shuttle system. This involves the conversion of fatty-acyl-CoA to fatty-acyl carnitine, which can readily cross the mitochondrial membrane. Once inside the matrix, the carnitine is removed, and the fatty-acyl-CoA is re-formed.

The breakdown of MCFAs within the mitochondria occurs through a cyclical process known as beta-oxidation. This process involves four main steps:

1. **Dehydrogenation:** The fatty-acyl-CoA is dehydrogenated by the enzyme acyl-CoA dehydrogenase, producing a trans-enoyl-CoA. This step removes two hydrogen atoms and generates FADH2, which enters the electron transport chain to produce ATP.

2. **Hydration:** The trans-enoyl-CoA is hydrated by the enzyme enoyl-CoA hydratase to form 3-hydroxyacyl-CoA.

3. **Oxidation:** The 3-hydroxyacyl-CoA is oxidized by the enzyme 3-hydroxyacyl-CoA dehydrogenase, producing 3-ketoacyl-CoA. This step generates NADH, which also enters the electron transport chain to produce ATP.

4. **Thiolysis:** The 3-ketoacyl-CoA is cleaved by the enzyme thiolase, resulting in the formation of acetyl-CoA and a shorter fatty-acyl-CoA.

The acetyl-CoA produced from beta-oxidation enters the citric acid cycle, where it is further oxidized to generate more ATP. The shorter fatty-acyl-CoA undergoes another round of beta-oxidation, continuing the process until the entire MCFA is broken down into acetyl-CoA.

MCFA metabolism is an important source of energy for many tissues, especially the liver, heart, and skeletal muscles. It plays a role in various physiological processes, including:

* **Energy production:** MCFAs are readily oxidized in the mitochondria, providing a rapid source of ATP.
* **Ketone body production:** In the liver, MCFAs can be converted into ketone bodies, which are used as an alternative energy source by the brain and other tissues during fasting or prolonged exercise.
* **Hormonal regulation:** MCFAs have been shown to influence the production and release of various hormones, including insulin and leptin.
* **Anti-inflammatory effects:** Some MCFAs, such as lauric acid, have been reported to have anti-inflammatory properties.

Overall, medium-chain fatty-acyl-CoA metabolic process is a crucial metabolic pathway for the breakdown and utilization of MCFAs, contributing to energy production and various physiological functions.'
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