Α-Ketoisocaproic acid

Α-Ketoisocaproic acid (also known as α-KIC and 2-Ketoisocaproate) is a metabolite of the branched-chain amino acid leucine. It is an important intermediate in the metabolic pathway known as the leucine degradation pathway, which is responsible for the breakdown and utilization of leucine in the body.

Structure and Properties

Α-Ketoisocaproic acid is a keto acid. It has a carboxylic acid group and a ketone group, making it an acid and a ketone simultaneously. The "isocaproic" part of its name refers to its isopropyl group, which is a branch off the main carbon chain.

Metabolism

Α-Ketoisocaproic acid is produced in the body from leucine through a process called transamination. This process involves the transfer of an amino group from leucine to a ketoglutarate molecule, producing α-KIC and glutamate. This reaction is catalyzed by the enzyme branched-chain amino acid transaminase.

Once formed, α-KIC can be further metabolized in one of two ways. It can be decarboxylated to form isovaleryl-CoA, a reaction catalyzed by the enzyme branched-chain α-keto acid dehydrogenase complex. Alternatively, it can be transaminated again to form leucine, in a reaction catalyzed by the same branched-chain amino acid transaminase.

Role in Human Health

Α-Ketoisocaproic acid plays a crucial role in human health. It is involved in the regulation of protein synthesis and protein degradation in muscle tissue. It also plays a role in the regulation of insulin secretion, and has been implicated in the development of insulin resistance.

In addition, α-KIC is used as a dietary supplement by bodybuilders and other athletes, as it is believed to help with muscle recovery and growth. However, the scientific evidence supporting these claims is limited.

See Also

• Leucine
• Branched-chain amino acid
• Keto acid
• Transamination
• Branched-chain α-keto acid dehydrogenase complex