Acetyl-CoA

Acetyl-CoA

2D structure of Acetyl-CoA

3D ball-and-stick model of Acetyl-CoA

Acetyl-CoA is a central metabolite in biochemistry, playing a critical role in the metabolism of carbohydrates, fats, and proteins. It is a key molecule in the citric acid cycle (also known as the Krebs cycle) and is involved in the synthesis and oxidation of fatty acids.

Structure

Acetyl-CoA is a complex molecule composed of an acetyl group attached to coenzyme A. The acetyl group is derived from pyruvate, which is the end product of glycolysis. Coenzyme A is a large molecule that contains a pantothenic acid moiety, a cysteamine group, and a 3'-phosphoadenosine diphosphate.

Function

Acetyl-CoA serves as a substrate for several important biochemical pathways:

• Citric Acid Cycle: Acetyl-CoA enters the citric acid cycle by combining with oxaloacetate to form citrate, which is then metabolized to produce ATP, NADH, and FADH2.
• Fatty Acid Synthesis: Acetyl-CoA is a precursor for the synthesis of fatty acids. It is converted to malonyl-CoA by the enzyme acetyl-CoA carboxylase, which is the first step in fatty acid biosynthesis.
• Ketone Body Production: In the liver, acetyl-CoA can be converted into ketone bodies during periods of low carbohydrate intake or prolonged exercise.
• Cholesterol Synthesis: Acetyl-CoA is also a precursor for the synthesis of cholesterol and other isoprenoids.

Metabolic Pathways

Pyruvate Dehydrogenase Complex

Reaction catalyzed by the pyruvate dehydrogenase complex

The pyruvate dehydrogenase complex is a multi-enzyme complex that converts pyruvate into acetyl-CoA. This reaction links glycolysis to the citric acid cycle and is a key regulatory point in cellular metabolism.

Beta-Oxidation

In the process of beta-oxidation, fatty acids are broken down into acetyl-CoA units, which can then enter the citric acid cycle for energy production.

Amino Acid Catabolism

Certain amino acids can be converted into acetyl-CoA through various catabolic pathways, contributing to the pool of acetyl-CoA available for energy production and biosynthesis.

Importance in Metabolism

Overview of metabolic pathways involving Acetyl-CoA

Acetyl-CoA is a pivotal molecule in metabolism, acting as a crossroads for various metabolic pathways. Its central role in energy production and biosynthesis makes it essential for cellular function and survival.

Related Pages

• Citric acid cycle
• Fatty acid metabolism
• Glycolysis
• Coenzyme A

Gallery

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  3D van der Waals model of Acetyl-CoA

Acetyl-CoA

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  2D structure of Acetyl-CoA

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  3D ball-and-stick model of Acetyl-CoA

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  3D van der Waals model of Acetyl-CoA

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  Pyruvate dehydrogenase complex reaction

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  Metabolism overview