How Effective Is Lysine for Acne?

The chemical name of lysine is 2,6-diaminohexanoic acid. Lysine is a basic essential amino acid. Because the lysine content in cereals is very low, and it is easily destroyed and lacked during processing, it is called the first restricted amino acid. ^[1]

Lysine is one of the essential amino acids for humans and mammals. The body cannot synthesize itself and must be supplemented from food. Lysine is mainly found in animal foods and legumes, and lysine is very low in cereals. ^[2] Lysine has positive nutritional significance in promoting human growth and development, strengthening the body's immunity, anti-virus, promoting fat oxidation, and alleviating anxiety, and can also promote the absorption of certain nutrients. Nutrients work in synergy to better exert the physiological functions of various nutrients. ^[2]

Chinese name: Lysine
Foreign name: Lysine

nickname: First restricted amino acid
Molecular formula: C6H14N202

Lysine exists

According to optical activity, lysine has three configurations of L-type (L-rotation), D-type (D-rotation) and DL-type (Racemic). Only the L-type can be used by living things.

L-lysine

Lysine The content of active ingredients is generally 77% -79%. Monogastric animals cannot synthesize lysine on their own and do not participate in transamination. After the amino groups of D-amino acid and L-amino acid are acetylated, they can be deaminated by the action of D-amino acid oxidase or L-amino acid oxidase. Irreversible, therefore, often manifests as insufficient in animal nutrition. ^[3]

Physical and Chemical Properties of Lysine

Generally speaking lysine refers to the L form. L-type lysine is needle-like crystals, darkens at 210 ° C, decomposes at 224.5 ° C, is easily soluble in water, slightly soluble in alcohol, and insoluble in ether. ^[4]

Lysine biochemical metabolism

Only the L-form of lysine is absorbed by the organism. Free lysine easily absorbs carbon dioxide in the air, making it difficult to obtain crystals. General products are in the form of lysine hydrochloride. Lysine is easily soluble in water. Compared with other amino acids, lysine is the most easily absorbed by oral administration. Ingestion of lysine in the body first enters the small intestinal mucosal cells from the small intestine cavity by active transport, and then enters the liver through the portal vein; in the liver, lysine is involved in protein synthesis along with other amino acids. Lysine catabolism is also carried out in the liver. It condenses with ketoglutarate to form yeast amino acids. The yeast amino acids are then converted into L--aminoadipate semialdehyde, which is finally converted to acetyl-CoA. Unlike other amino acids, lysine does not participate in transamination, and the deamination reaction is irreversible, so the catabolism of lysine is very special. Lysine is a sugar- and ketogenic amino acid, so it can participate in the formation of D-glucose, glycogen, and lipids, and ultimately generate energy. ^[2]

Human absorption experiments show that the absorption rate of lysine supplements is the same as the absorption rate of lysine in food proteins, indicating that lysine supplements are an effective way to improve dietary lysine deficiency. Studies have found that lysine is rapidly transported to muscle tissue within 5-7 hours after eating. Unlike other essential amino acids, lysine accumulates more in the cells of muscle tissue, suggesting that muscle tissue is a reservoir of free lysine in the body. Of all the essential amino acids, lysine is stored most in the body. ^[2]

Lysine biosynthetic pathway

The biosynthetic pathway of lysine was gradually identified after 1950. The biosynthetic pathway of lysine is different from other amino acids, depending on the type of microorganism. Bacterial lysine biosynthetic pathways require the synthesis of lysine via diaminopimelate (DAP). The lysine biosynthetic pathway of yeast and mold requires the synthesis of lysine through -aminoadipate. The same is the diaminopimelate synthesis lysine pathway. Different bacteria have different regulation mechanisms for lysine biosynthesis. ^[5]

Lysine aspartate pathway

Aspartic acid is reacted to synthesize diaminopimelate (ADP), and then to lysine ^[6] .

Lysine biosynthetic pathway ^[1] The lysine synthesis pathway in yeast requires aspartic acid to synthesize -aminoethanedioic acid, which is catalyzed by lysX , lysZ , lysY , lysJ , argD , lysK and argE gene products to generate acetylated intermediates. N-acetyl-L--aminooxalic acid and the like generate lysine. ^[7]

The aspartic acid pathway is also known as the diaminopimelate pathway. This pathway is mostly present in bacteria, green algae, protozoa, and higher plants, and can also synthesize threonine, methionine, and isoleucine. ^[8]

- Lysine alpha-aminoadipate pathway

Synthesis from 2-ketoglutarate and acetyl-CoA via the -aminoethanedioic acid pathway. The five-step reaction is catalyzed by isocitrate synthase, aconitate synthase / cis aconitate synthase, aconitate dehydrogenase, and 2-ketoglutarate and acetyl-CoA to form -aminoethanedioate . In the second reaction, -aminoethanedioic acid is catalyzed to produce lysine by -aminoethanedioate reductase, yeast amino acid reductase, and yeast amino acid dehydrogenase. ^[7]

The alpha-aminooxalic acid pathway is found in higher fungi and archaea. ^[7]

Lysine Food Source

Lysine is one of the components that make up protein. Generally, protein-rich foods contain lysine.

nut Foods rich in lysine are animal foods (such as lean meats of fish, poultry, fish, shrimp, crab, shellfish, eggs and dairy products), beans (including soybeans, miscellaneous beans and their products). In addition, lysine content in nuts such as almonds, hazelnuts, peanut kernels, and pumpkin kernels is also relatively high. The lysine content in cereals is very low and easily destroyed during processing, so it is the first limiting amino acid in cereals. ^[2]

Lysine requirement

Different populations (infants, young children, adults) require different amounts of lysine. In 2005, based on the results of the research at that time, the US Food and Nutrition Board set the adult lysine requirement at 31 mg · kg ^-1 · d ^-1 . ^[2]

In 2007, the WHO / FAO / UNU Expert Committee determined that the lysine requirement was 30 mg · kg ^-1 · d ^-1 based on the results of relevant human trials. This value is currently generally accepted. The infant / adolescent and adolescent lysine requirements determined by WHO / FAO are (mg · kg ^-1 · d ^-1 ): 1 month (119), 2 months (87), 3 months (75), 4 Months of age (68), 6 months of age (65), 1-2 years (45), 3-10 years (35), 11-14 years (35), 15-18 years (33). At present, China has not formulated a recommended dietary lysine intake standard for people who meet the dietary habits of Chinese residents. ^[2]

Lysine digestibility and utilization

D-lysine and L-lysine have different absorption efficiencies. D-lysine can hardly be absorbed and utilized. The main biological activity is L-lysine. The -amino group of lysine is very active and easily combines with the active carbonyl group in the feed to form a complex that is difficult to be absorbed and utilized. ^[3]

Lysine nutritional physiological function

Lysine can regulate the body's metabolic balance. Lysine provides structural components for the synthesis of carnitine, and carnitine promotes the synthesis of fatty acids in cells. Adding a small amount of lysine to food can stimulate the secretion of pepsin and gastric acid, improve gastric juice secretion, and play a role in increasing appetite and promoting young children's growth and development. Lysine can also increase the absorption of calcium and its accumulation in the body, and accelerate bone growth. If lysine is lacking, it will cause insufficient secretion of gastric juice and anorexia and nutritional anemia, which will cause the central nervous system to be blocked and stunted. Lysine can also be used as a diuretic adjuvant in medicine to treat lead poisoning caused by decreased chloride in the blood. It can also form salts with acidic drugs (such as salicylic acid) to alleviate adverse reactions. Can inhibit severe hypertension, and studies have shown that lysine supplementation can accelerate the recovery of herpes infections and inhibit their recurrence. ^[1]

Participate in the synthesis of body proteins

lysine

Lysine, as an essential amino acid in the body, is involved in the synthesis of various proteins such as skeletal muscle, enzymes, serum proteins, peptide hormones, etc. ^[2]

Involved in energy metabolism

Lysine is involved in the biosynthesis of carnitine in the body. Carnitine plays an important role in fat metabolism and is an essential cofactor for fat metabolism. Lysine is one of the precursor substances for carnitine synthesis, so lysine supplementation can accelerate fat metabolism in the body. Lysine has a strong function of crossing the blood-brain barrier, can directly enter the brain tissue, affect the respiratory chain, and provide the necessary energy source for the repair of nerve cells and normal physiological activities. ^[2]

Promote mineral absorption and bone growth

Lysine can chelate with mineral elements such as calcium and iron to form soluble small molecule monomers, and promote the absorption of these mineral elements. ^[2]

Enhance immune function

Lysine is considered to be a non-specific bridge molecule, which can connect antigens to T cells and cause T cells to produce specific effects on antigens. ^[2]

Treating herpes simplex virus infection

Studies have also found that lysine supplementation can treat herpes simplex virus infections. ^[2]

Lysine fermentation process

Lysine fermentation can be divided into two-step fermentation (also known as precursor addition) and direct fermentation. ^[1]

Lysine two-step fermentation

The two-step fermentation method was developed in the early 1950s. The two-step fermentation method uses lysine precursor diaminopimelate as a raw material and decarboxylates the enzyme produced by the microorganism (diaminopimelate decarboxylase) into Lysine. Since diaminopimelate is also produced by fermentation, it is called a step fermentation. After the 1970s, Japan used immobilized diaminopimelate decarboxylase or bacterial cells containing this enzyme to continuously meso 2,6-diaminopimelate decarboxylate to continuously produce lysine, which improved this process. Despite this, the process is still more complicated and has now been replaced by direct fermentation. ^[1]

Lysine direct fermentation

Direct fermentation is a widely used lysine production method. Commonly used raw materials are sugar cane or sugar beet waste molasses, starch hydrolysate and other cheap sugary raw materials. In addition, acetic acid, ethanol, etc. are also optional raw materials. The main microorganisms producing lysine by direct fermentation include mutants of Corynebacterium glutamicum, Brevibacterium flavum, and Brevibacterium lactofermentum. This method was developed in the late 1950s. Since the 1970s, due to the development of breeding technology, some mutants with multiple genetic markers have been bred to make the process mature and the yield of lysine has doubled. . The highest acid yield in industrial production has been increased to 100-120g per liter of fermentation, and the extraction rate has reached about 80% -90%. ^[1]

Lysine production status

L-lysine was originally isolated from protein hydrolysates.

Lysine Using animal blood meal as raw material, this method is characterized by simple process, but the source of raw material is limited, which is only suitable for small-scale production. Later, chemical synthesis and enzymatic methods appeared. The main synthetic methods used were the DMS method in the Netherlands and the Toray method in Japan. The biggest disadvantage of this method is the use of highly toxic raw material phosgene, which may leave catalysts, poor product safety, and serious Environmental issues. In 1960, Japan first produced by microbial fermentation. The microbial fermentation to produce amino acids is to artificially release the metabolic control mechanism of amino acid biosynthesis, so that it accumulates a large number of required amino acids. The L-type stereospecificity of amino acids determines that the process of producing amino acids by fermentation is simpler and faster than chemical synthesis. China began research on lysine strain selection and fermentation in the mid-1960s, but it is difficult to industrialize due to low yield. It was not until the industrialization of lysine in the world in the late 1970s and early 1980s that China made a breakthrough. At present, most of the lysine-producing enterprises in the world adopt fermentation method, and the production is L-type lysine, and the production process is basically mature. ^[8]

The strains used in the industrial fermentation to produce lysine are mainly fine variants such as Corynebacterium and Brevibacterium. Corynebacterium has very high economic value, and Corynebacterium glutamicum is the most widely used. In addition, lysine production has also been reported in E. coli, Brevibacterium flavum, Saccharomyces cerevisiae, Brevibacterium lactofermentum, Candida and the like. ^[8]

There are four main types of lysine-producing microorganisms: wild-type, trophic mutant, regulatory mutant, and nutrition-regulated mutant. In industry, lysine production is improved by optimizing fermentation strains (mutagenesis and genetic engineering means) and changing fermentation conditions (stirring speed, pH, dissolved oxygen, temperature and CO ₂ ). The main methods to obtain high-yielding microbial strains are traditional mutagenesis methods (ultraviolet rays, x-rays, nitrogen mustard, and nitroso esters), protoplast fusion, and genetic engineering methods. It has been reported that the lysine produced by the mutagenized strain is increased by 40% -50%. Mutagenic strains use low-cost carbon sources as raw materials for fermentation, such as various starch hydrolyzed sugars, honey, acetic acid, and ethanol, to produce lysine by fermentation, and obtain feed-grade lysine through isolation, concentration, evaporation, crystallization, and drying production processes Amino acid, re-refined to obtain food-grade, pharmaceutical-grade products. ^[8]