valine biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of valine, 2-amino-3-methylbutanoic acid. [GOC:ai]

The valine biosynthetic process, a crucial step in protein synthesis, involves a complex series of enzymatic reactions starting from pyruvate, a common metabolic intermediate. This pathway is essential for the production of valine, an essential amino acid that cannot be synthesized by humans and must be obtained through diet.

The biosynthesis of valine occurs in three main stages:

**1. Formation of α-ketoisovalerate:** This initial step involves the condensation of pyruvate and a molecule of acetyl-CoA, catalyzed by the enzyme acetohydroxyacid synthase. This enzyme is crucial for the synthesis of branched-chain amino acids (BCAAs), including valine, leucine, and isoleucine.

**2. Reduction of α-ketoisovalerate:** The α-ketoisovalerate produced in the first step is then reduced to α-hydroxyisovalerate by the enzyme ketol-acid reductoisomerase. This reaction requires the coenzyme NADPH, which acts as an electron donor.

**3. Transamination of α-hydroxyisovalerate:** The final step in valine biosynthesis involves the transamination of α-hydroxyisovalerate to valine. This reaction is catalyzed by the enzyme branched-chain aminotransferase, which transfers an amino group from another amino acid, such as glutamate, to the α-hydroxyisovalerate molecule.

The valine biosynthetic process is tightly regulated at multiple levels, ensuring that the appropriate amount of valine is produced to meet cellular demands. Regulation occurs through feedback inhibition, where the end product, valine, inhibits the activity of key enzymes involved in the pathway.

Valine, as an essential amino acid, plays a vital role in various cellular functions, including protein synthesis, muscle growth, and the maintenance of immune system function. Deficiencies in valine can lead to various health issues, including growth retardation, immune dysfunction, and impaired wound healing.

In summary, the valine biosynthetic process is a critical pathway for the production of this essential amino acid, involving a series of enzymatic reactions that are tightly regulated to ensure proper cellular function and overall health.'
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Proteins (3)

Compounds (2)