Fatty Acyl-CoA

Definition

Fatty acyl-CoA refers to the coenzyme A (CoA) thioester derivative of a fatty acid, which is the activated form of a fatty acid that can undergo β-oxidation to generate energy for the cell. This term is crucial in understanding the catabolism of triacylglycerols through the process of β-oxidation.

5 Must Know Facts For Your Next Test

1. Fatty acyl-CoA is the activated form of a fatty acid that can undergo β-oxidation to generate energy for the cell.
2. The conversion of fatty acids to fatty acyl-CoA is catalyzed by the enzyme acyl-CoA synthetase, which attaches coenzyme A to the carboxyl group of the fatty acid.
3. Fatty acyl-CoA is the substrate for the β-oxidation pathway, where it undergoes a series of enzymatic reactions to break down the fatty acid chain and produce acetyl-CoA units.
4. The acetyl-CoA units generated from β-oxidation can then enter the citric acid cycle to produce ATP, the primary energy currency of the cell.
5. The formation of fatty acyl-CoA is a crucial step in the catabolism of triacylglycerols, as it allows for the breakdown and utilization of stored fat as an energy source.

Review Questions

• Explain the role of fatty acyl-CoA in the catabolism of triacylglycerols.
  • Fatty acyl-CoA is the activated form of fatty acids that allows them to undergo β-oxidation, the process by which fatty acids are broken down to generate acetyl-CoA units. This is a crucial step in the catabolism of triacylglycerols, the primary storage form of fat in the body. The conversion of triacylglycerols to fatty acyl-CoA, catalyzed by enzymes like acyl-CoA synthetase, enables the utilization of stored fat as an energy source for the cell.
• Describe the relationship between fatty acyl-CoA and the citric acid cycle.
  • The acetyl-CoA units generated from the β-oxidation of fatty acyl-CoA can enter the citric acid cycle, also known as the Krebs cycle. In the citric acid cycle, the acetyl-CoA is further oxidized, generating reducing equivalents (NADH and FADH2) that can be used by the electron transport chain to produce ATP, the primary energy currency of the cell. This coupling of fatty acid catabolism (β-oxidation) and the citric acid cycle allows for the efficient utilization of stored fat as an energy source for the body.
• Evaluate the importance of the conversion of fatty acids to fatty acyl-CoA in the context of energy metabolism.
  • The conversion of fatty acids to their activated fatty acyl-CoA form is a critical step in energy metabolism, as it allows for the breakdown and utilization of stored fat as an energy source. Fatty acyl-CoA is the substrate for the β-oxidation pathway, which generates acetyl-CoA units that can then enter the citric acid cycle to produce ATP. This process is particularly important during periods of fasting or starvation, when the body needs to rely on stored fat as a primary energy source. The ability to convert fatty acids to fatty acyl-CoA and subsequently undergo β-oxidation is a key adaptive mechanism that enables the body to maintain energy homeostasis and meet its energy demands, even in the absence of dietary carbohydrates or proteins.

Related terms

Triacylglycerol: Also known as triglyceride, triacylglycerol is the main storage form of fat in the body, consisting of three fatty acid chains esterified to a glycerol backbone.

β-Oxidation: The catabolic process by which fatty acids are broken down to acetyl-CoA units, which can then enter the citric acid cycle to produce ATP.

Acyl-CoA Synthetase: The enzyme responsible for activating fatty acids by converting them to their coenzyme A (CoA) thioester derivatives, known as fatty acyl-CoA.