(S)-4-Amino-2-methylbutanoic acid

(S)-4-Amino-2-methylbutanoic acid, also known as L-Leucine or Leucine, is an essential amino acid that plays a critical role in protein synthesis and various metabolic functions. It is one of the three branched-chain amino acids (BCAAs), along with Isoleucine and Valine.

Structure and Properties

(S)-4-Amino-2-methylbutanoic acid has the chemical formula C₆H₁₃NO₂ and a molecular weight of 131.17 g/mol. It is characterized by a branched aliphatic side chain, which makes it hydrophobic. The "S" in its name indicates that it is the L-enantiomer, which is the biologically active form found in proteins.

Biological Role

Leucine is a key regulator of the mTOR signaling pathway, which is crucial for cell growth and protein synthesis. It is also involved in the regulation of blood sugar levels, growth and repair of muscle and bone tissues, and production of growth hormones.

Metabolism

Leucine is metabolized primarily in the liver, adipose tissue, and muscle. It is converted into acetyl-CoA and acetoacetate, which can be used for energy production. Leucine is unique among the amino acids for its ability to stimulate muscle protein synthesis directly.

Dietary Sources

Leucine is found in high concentrations in animal proteins such as meat, dairy products, and eggs. Plant-based sources include soy products, legumes, and nuts. As an essential amino acid, it must be obtained through the diet.

Clinical Significance

Leucine supplementation is often used by athletes to enhance muscle growth and improve exercise performance. It is also being studied for its potential benefits in muscle wasting conditions such as sarcopenia and cachexia.

Also see

• Amino acid
• Branched-chain amino acid
• Protein synthesis
• mTOR signaling pathway
• Essential amino acid