Alpha-ketoglutarate

An important biological compound involved in the Krebs cycle and amino acid metabolism

Alpha-ketoglutarate

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Chemical formula	CHNO
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Alpha-ketoglutarate (α-KG) is a key intermediate in the Krebs cycle (also known as the citric acid cycle or TCA cycle), which is a central metabolic pathway in cellular respiration. It plays a crucial role in the metabolism of amino acids and the production of energy in the form of adenosine triphosphate (ATP).

Structure and Properties

Alpha-ketoglutarate is a 5-carbon dicarboxylic acid with the chemical formula C₅H₆O₅. It is the keto acid form of glutamic acid, and it contains a ketone group at the alpha position relative to the carboxylic acid group.

Biological Role

Alpha-ketoglutarate is involved in several important biological processes:

Krebs Cycle

In the Krebs cycle, alpha-ketoglutarate is formed from isocitrate through the action of the enzyme isocitrate dehydrogenase. It is then converted into succinyl-CoA by the enzyme alpha-ketoglutarate dehydrogenase complex, releasing carbon dioxide and reducing NAD+ to NADH, which is used in the electron transport chain to generate ATP.

Amino Acid Metabolism

Alpha-ketoglutarate is a key molecule in the transamination reactions that convert amino acids into their corresponding keto acids. It acts as an amino group acceptor, forming glutamate in the process. This is crucial for the synthesis and degradation of amino acids.

Nitrogen Metabolism

In addition to its role in amino acid metabolism, alpha-ketoglutarate is involved in the urea cycle, where it helps in the removal of excess nitrogen from the body.

Clinical Significance

Alpha-ketoglutarate has been studied for its potential therapeutic effects. It is thought to have antioxidant properties and may play a role in reducing oxidative stress. Some studies suggest that alpha-ketoglutarate supplementation could be beneficial in conditions such as chronic kidney disease and muscle wasting.

Also see

• Krebs cycle
• Amino acid metabolism
• Glutamic acid
• Succinyl-CoA
• NADH