Llysine

Lysine, or L-lysine, is an essential amino acid used in the synthesis of proteins. It is one of the nine essential amino acids for humans and must be obtained from the diet because humans cannot synthesize it endogenously. In proteins, lysine is encoded by the codons AAA and AAG. It is a basic, positively charged amino acid with a relatively long aliphatic side chain, contributing to protein structure and function.

Dietary sources include meat, fish, dairy products, eggs, soy, beans and lentils, and grains such as quinoa. Vegetarians and vegans often rely on combinations of legumes and cereals to ensure adequate lysine intake.

Biological roles: Lysine is essential for protein synthesis and growth. It participates in collagen cross-linking, acts as a precursor to the molecule carnitine, and can undergo post-translational modifications such as acetylation and methylation of lysine residues that regulate protein function.

Deficiency and health effects: Lysine deficiency is rare in healthy populations but may occur with severe malnutrition or certain metabolic disorders, leading to growth impairment, anemia, poor wound healing, and increased susceptibility to infections.

Industrial and medical uses: Lysine is produced industrially by microbial fermentation and is widely added to animal feed as a nutrient supplement. It is used in some dietary supplements and marketed for herpes simplex virus outbreaks, though clinical evidence is mixed and medical advice is recommended.

Safety: Generally well tolerated; high-dose lysine can cause abdominal cramps, diarrhea, and nausea. It may influence arginine metabolism and should be used with caution by people with kidney disease or those taking certain medications.