Lysiinin

Lysiinin, known in English as lysine, is an essential amino acid required for human life. It is one of the nine amino acids that humans must obtain from the diet because they cannot be synthesized endogenously. In proteins, lysine is typically present in the L-configuration (L-lysine) and carries a positively charged (basic) side chain at physiological pH, contributing to the overall charge and structure of proteins.

Lysine plays several roles in metabolism and health. It is crucial for protein synthesis and tissue growth and repair, including collagen formation. It also supports calcium absorption, immune function, and the production of enzymes, hormones, and carnitine, a molecule involved in fatty acid metabolism. Dietary lysine is found in animal products such as meat, fish, eggs, and dairy, as well as in plant sources like soy, beans, lentils, quinoa, and certain nuts. Cereals are relatively lysine-poor, making balanced combinations with lysine-rich foods important in vegetarian or vegan diets.

Deficiency is uncommon in balanced diets but can occur with restrictive diets or certain medical conditions. Symptoms may include slowed growth in children, reduced nitrogen balance, anemia, and impaired immune response. The average daily requirement varies with age, sex, and life stage; guidelines from international health bodies suggest an intake on the order of a few dozen milligrams per kilogram of body weight per day.

Industrially, lysine is produced predominantly by microbial fermentation and used as a feed additive to improve the amino acid profile of low-lysine cereals in livestock nutrition. It is also marketed as a dietary supplement and food fortification ingredient. In medical use, lysine has been studied for herpes simplex virus infections, with evidence of modest benefit in some cases, though results are not uniform.

Safety at recommended intakes is generally good; excessive lysine intake can cause abdominal discomfort and diarrhea and may interact with arginine metabolism, so individuals with kidney disease or on certain medications should consult a healthcare provider.