What Is L-Leucine?
L-leucine, a branched-chain amino acid (BCAA) along with valine and isoleucine, is one of the 20 amino acids that constitute proteins. It has an isobutyl group on its side chain, making it highly hydrophobic. L-leucine, which exists in L- and D-forms, is found in proteins as the L-isomer.
As an essential amino acid, humans cannot synthesize L-leucine; it must be acquired through diet.
Physicochemical Properties of L-Leucine
1. Name
English name: L-leucine
IUPAC name: (2S)-2-amino-4-methylpentanoic acid
3-letter abbreviation: Leu
1-letter abbreviation: L
2. Molecular Formula
C6H13NO2
3. Molecular Weight
131.17
4. Melting Point
293-295°C (decomposition)
5. Solvent Solubility
Slightly soluble in water, insoluble in ethanol.
6. Taste
Slightly bitter
Effects, Indications, and Uses of L-leucine
As a BCAA, L-leucine plays a crucial role in muscle fiber proteins. It activates enzymes needed for protein synthesis and induces muscle protein synthesis. Consequently, L-leucine and other BCAAs are popular supplements for strength training. Additionally, L-leucine is known to improve liver function, relieve stress, enhance glucose tolerance and insulin sensitivity, and promote hair growth. It is used in pharmaceuticals for amino acid supplementation and as a food additive.
Relationship Between L-Leucine Intake and Disease
L-leucine is abundant in various foods, making deficiency rare. However, insufficient intake may impair liver function and reduce insulin secretion. Excessive intake can disrupt the balance with other amino acids, potentially weakening the immune system.
Foods Rich in L-Leucine
Sources of L-leucine include liver, tuna, mackerel, chicken, dairy products, soy products, eggs, and yogurt.