Lysine

Lysine

Overview
Lysine is an α-amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 with the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 HO2CCH(NH2)(CH2)4NH2. It is an essential amino acid
Essential amino acid
An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism , and therefore must be supplied in the diet.-Essentiality vs. conditional essentiality in humans:...

, which means that the human body cannot synthesize it. Its codons are AAA and AAG.

Lysine is a base, as are arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...

 and histidine
Histidine
Histidine Histidine, an essential amino acid, has a positively charged imidazole functional group. It is one of the 22 proteinogenic amino acids. Its codons are CAU and CAC. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans...

. The ε-amino group often participates in hydrogen bonding and as a general base in catalysis
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

. (The ε-amino group, which is attached to the NH3+ group, is the fifth carbon down from the α-carbon, which is attached to the carboxyl (C=OOH) group.)

Common posttranslational modification
Posttranslational modification
Posttranslational modification is the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis, and thus gene expression, for many proteins....

s include methylation of the ε-amino group, giving methyl-
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

, dimethyl-
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

, and trimethyllysine
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

.
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Encyclopedia
Lysine is an α-amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 with the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 HO2CCH(NH2)(CH2)4NH2. It is an essential amino acid
Essential amino acid
An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism , and therefore must be supplied in the diet.-Essentiality vs. conditional essentiality in humans:...

, which means that the human body cannot synthesize it. Its codons are AAA and AAG.

Lysine is a base, as are arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...

 and histidine
Histidine
Histidine Histidine, an essential amino acid, has a positively charged imidazole functional group. It is one of the 22 proteinogenic amino acids. Its codons are CAU and CAC. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans...

. The ε-amino group often participates in hydrogen bonding and as a general base in catalysis
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

. (The ε-amino group, which is attached to the NH3+ group, is the fifth carbon down from the α-carbon, which is attached to the carboxyl (C=OOH) group.)

Common posttranslational modification
Posttranslational modification
Posttranslational modification is the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis, and thus gene expression, for many proteins....

s include methylation of the ε-amino group, giving methyl-
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

, dimethyl-
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

, and trimethyllysine
Methyllysine
In proteins, the amino acid residue lysine can be methylated once, twice or thrice on its terminal sidechain ammonium group.Such methylated lysines play an important role in epigenetics; the methylation of specific lysines of certain histones in a nucleosome alters the binding of the surrounding...

. The latter occurs in calmodulin
Calmodulin
Calmodulin is a calcium-binding protein expressed in all eukaryotic cells...

. Other posttranslational modification
Posttranslational modification
Posttranslational modification is the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis, and thus gene expression, for many proteins....

s at lysine residues include acetylation
Acetylation
Acetylation describes a reaction that introduces an acetyl functional group into a chemical compound...

 and ubiquitination. Collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

 contains hydroxylysine
Hydroxylysine
5-Hydroxylysine is an amino acid with the molecular formula C6H14N2O3. It was first discovered in 1921 by Donald Van Slyke. It is a hydroxy derivative of lysine. It is most widely known as a component of collagen....

, which is derived from lysine by lysyl hydroxylase
Lysyl hydroxylase
Lysyl hydroxylase is an oxygenase enzyme that catalyzes the hydroxylation of lysine to hydroxylysine. This reaction is necessary to the formation and stabilization of collagen. It takes place following protein synthesis...

. O-Glycosylation
Glycosylation
Glycosylation is the reaction in which a carbohydrate, i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule . In biology glycosylation refers to the enzymatic process that attaches glycans to proteins, lipids, or other organic molecules...

 of hydroxylysine residues in the endoplasmic reticulum
Endoplasmic reticulum
The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...

 or Golgi apparatus
Golgi apparatus
The Golgi apparatus is an organelle found in most eukaryotic cells. It was identified in 1898 by the Italian physician Camillo Golgi, after whom the Golgi apparatus is named....

 is used to mark certain proteins for secretion
Secretion
Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...

 from the cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.

Biosynthesis


As an essential amino acid, lysine is not synthesized in animals, hence it must be ingested as lysine or lysine-containing proteins. In plants and bacteria, it is synthesized from aspartic acid
Aspartic acid
Aspartic acid is an α-amino acid with the chemical formula HOOCCHCH2COOH. The carboxylate anion, salt, or ester of aspartic acid is known as aspartate. The L-isomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins...

 (aspartate):
  • L-aspartate is first converted to L-aspartyl-4-phosphate by aspartokinase
    Aspartokinase
    Aspartokinase is an enzyme that catalyzes the phosphorylation of the amino acid aspartate. This reaction is the first step in the biosynthesis of three essential amino acids: methionine, lysine, and threonine, known as the "aspartate family"...

     (or Aspartate kinase). ATP
    Adenosine triphosphate
    Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...

     is needed as an energy source for this step.
  • β-Aspartate semialdehyde dehydrogenase
    Dehydrogenase
    A dehydrogenase is an enzyme that oxidises a substrate by a reduction reaction that transfers one or more hydrides to an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.-Examples:...

     converts this into β-aspartyl-4-semialdehyde (or β-aspartate-4-semialdehyde). Energy from NADPH
    Nicotinamide adenine dinucleotide phosphate
    Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or TPN in older notation , is a coenzyme used in anabolic reactions, such as lipid and nucleic acid synthesis, which require NADPH as a reducing agent....

     is used in this conversion.
  • Dihydrodipicolinate synthase
    Dihydrodipicolinate synthase
    In enzymology, a dihydrodipicolinate synthase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are L-aspartate 4-semialdehyde and pyruvate, whereas its two products are -2,3-dihydropyridine-2,6-dicarboxylate and H2O.This enzyme belongs to the family of...

     adds a pyruvate
    Pyruvic acid
    Pyruvic acid is an organic acid, a ketone, as well as the simplest of the alpha-keto acids. The carboxylate ion of pyruvic acid, CH3COCOO−, is known as pyruvate, and is a key intersection in several metabolic pathways....

     group to the β-aspartyl-4-semialdehyde, and two water molecules are removed. This causes cyclization
    Cyclic compound
    In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring.While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. ...

     and gives rise to 2,3-dihydrodipicolinate.
  • This product is reduced to 2,3,4,5-tetrahydrodipicolinate (or Δ1-piperidine-2,6-dicarboxylate, in the figure: (S)-2,3,4,5-tetrahydropyridine-2,6-dicarboxylate) by dihydrodipicolinate reductase
    Dihydrodipicolinate reductase
    In enzymology, a dihydrodipicolinate reductase is an enzyme that catalyzes the chemical reaction-2,3,4,5-tetrahydropyridine-2,6-dicarboxylate + NAD+ \rightleftharpoons 2,3-dihydrodipicolinate + NADH + H+...

    . This reaction consumes a NADPH molecule.
  • Tetrahydrodipicolinate N-acetyltransferase
    Tetrahydrodipicolinate N-acetyltransferase
    In enzymology, a tetrahydrodipicolinate N-acetyltransferase is an enzyme that catalyzes the chemical reactionThe 3 substrates of this enzyme are acetyl-CoA, -2,3,4,5-tetrahydropyridine-2,6-dicarboxylate, and H2O, whereas its two products are CoA and L-2-acetamido-6-oxoheptanedioate.This enzyme...

     opens this ring and gives rise to N-succinyl-L-2-amino-6-oxoheptanedionate (or N-acyl-2-amino-6-oxopimelate). Two water molecules and one acyl-CoA
    Acyl-CoA
    Acyl-CoA is a group of coenzymes involved in the metabolism of fatty acids. It is a temporary compound formed when coenzyme A attaches to the end of a long-chain fatty acid inside living cells. The compound undergoes beta oxidation, forming one or more molecules of acetyl-CoA...

     (succinyl-CoA) enzyme are used in this reaction.
  • N-succinyl-L-2-amino-6-oxoheptanedionate is converted into N-succinyl-LL-2,6-diaminoheptanedionate (N-acyl-2,6-diaminopimelate). This reaction is catalyzed by the enzyme succinyl diaminopimelate aminotransferase. A glutaric acid
    Glutaric acid
    Glutaric acid is the organic compound with the formula HO2C3CO2H. Although the related "linear" dicarboxylic acids adipic and succinic acids are water-soluble only to a few percent at room temperature, the water-solubility of glutaric acid is over 50%....

     molecule is used in this reaction and an oxoacid
    Oxoacid
    An oxoacid is an acid that contains oxygen. To be more specific, it is an acid that:#contains oxygen#contains at least one other element#has at least one hydrogen atom bound to oxygen#forms an ion by the loss of one or more protons....

     is produced as a byproduct.
  • N-succinyl-LL-2,6-diaminoheptanedionate (N-acyl-2,6-diaminopimelate)is converted into LL-2,6-diaminoheptanedionate (L,L-2,6-diaminopimelate) by succinyl diaminopimelate desuccinylase (acyldiaminopimelate deacylase). A water molecule is consumed in this reaction and a succinate is produced a byproduct.
  • LL-2,6-diaminoheptanedionate is converted by diaminopimelate epimerase
    Diaminopimelate epimerase
    In enzymology, a diaminopimelate epimerase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, LL-2,6-diaminoheptanedioate, and one product, meso-diaminoheptanedioate....

     into meso-2,6-diamino-heptanedionate (meso-2,6-diaminopimelate).
  • Finally, meso-2,6-diamino-heptanedionate is converted into L-lysine by diaminopimelate decarboxylase
    Diaminopimelate decarboxylase
    In enzymology, a diaminopimelate decarboxylase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, meso-2,6-diaminoheptanedioate, and two products, L-lysine and CO2....

    .

Enzymes involved in this biosynthesis include:
  1. Aspartokinase
    Aspartokinase
    Aspartokinase is an enzyme that catalyzes the phosphorylation of the amino acid aspartate. This reaction is the first step in the biosynthesis of three essential amino acids: methionine, lysine, and threonine, known as the "aspartate family"...

  2. β-Aspartate semialdehyde dehydrogenase
    Dehydrogenase
    A dehydrogenase is an enzyme that oxidises a substrate by a reduction reaction that transfers one or more hydrides to an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.-Examples:...

  3. Dihydropicolinate synthase
    Synthase
    In biochemistry, a synthase is an enzyme that catalyses a synthesis process.Following the EC number classification, they belong to the group of ligases, with lyases catalysing the reverse reaction....

  4. Δ1-Piperidine-2,6-dicarboxylate dehydrogenase
  5. N-succinyl-2-amino-6ketopimelate synthase
  6. Succinyl diaminopimelate aminotransferase
  7. Succinyl diaminopimelate desuccinylase
  8. Diaminopimelate epimerase
  9. Diaminopimelate decarboxylase.

Metabolism


Lysine is metabolised
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 in mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s to give acetyl-CoA
Acetyl-CoA
Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its main function is to convey the carbon atoms within the acetyl group to the citric acid cycle to be oxidized for energy production. In chemical structure, acetyl-CoA is the thioester...

, via an initial transamination
Transamination
There are two chemical reactions known as transamination . The first is the reaction between an amino acid and an alpha-keto acid...

 with α-ketoglutarate. The bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l degradation of lysine yields cadaverine
Cadaverine
Cadaverine is a foul-smelling compound produced by protein hydrolysis during putrefaction of animal tissue. Cadaverine is a toxic diamine with the formula NH25NH2, which is similar to putrescine...

 by decarboxylation
Decarboxylation
Decarboxylation is a chemical reaction that releases carbon dioxide . Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carbonation, the addition of CO2 to...

.

Allysine
Allysine
Allysine is a derivative of Lysine, used in the production of elastin and collagen. It is produced by the actions of the enzyme lysyl oxidase in the extracellular matrix and is essential in the crosslink formation that stabilizes collagen and elastin....

 is a derivative of lysine, used in the production of elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...

 and collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

. It is produced by the actions of the enzyme lysyl oxidase
Lysyl oxidase
Lysyl oxidase also known as protein-lysine 6-oxidase is a protein that, in humans, is encoded by the LOX gene. Its inhibition can cause lathyrism, but, at the same time, its upregulation by tumor cells may promote metastasis of the existing tumor, causing it to become malignant and cancerous.-...

 on lysine in the extracellular matrix and is essential in the crosslink formation that stabilizes collagen and elastin.

Synthesis


Synthetic, racemic lysine has long been known. A practical synthesis starts from caprolactam
Caprolactam
Caprolactam is an organic compound with the formula 5CNH. This colourless solid is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually...

. Industrially, L-lysine is usually manufactured by a fermentation process using Corynebacterium glutamicum; production exceeds 600,000 tons a year.

Dietary sources


The nutritional requirement
Nutrition
Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....

 per day, in milligrams of lysine per kilogram of body weight, is: infants (3–4 months) 103, children (2 years) 64, older children (10–12 years) 60 to 44, adults 12. For a 70 kg adult, 12 milligrams of lysine per kilogram of body weight is 0.84 grams of lysine. Good sources of lysine are foods rich in protein such as soy
Soy protein
Soy protein is a protein that is isolated from soybean. It is made from dehulled, defatted soybean meal. Dehulled and defatted soybeans are processed into three kinds of high protein commercial products : soy flour, concentrates, and isolates. Soy protein isolate has been used since 1959 in foods ...

, as well as meat
Meat
Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...

 (specifically red meat, lamb, pork, and poultry), cheese (particularly Parmesan), certain fish (such as cod and sardines), and eggs.

Lysine is the limiting amino acid (the essential amino acid found in the smallest quantity in the particular foodstuff) in most cereal grains, but is plentiful in most pulses
Pulse (legume)
A pulse is an annual leguminous crop yielding from one to twelve seeds of variable size, shape, and color within a pod. Pulses are used for food and animal feed. The term "pulse", as used by the Food and Agricultural Organization , is reserved for crops harvested solely for the dry seed...

 (legumes). Consequently, meals that combine cereal grains and legumes, such as the Indian
Indian cuisine
Indian cuisine consists of thousands of regional cuisines which date back thousands of years. The dishes of India are characterised by the extensive use of various Indian spices, herbs, vegetables and fruit. Indian cuisine is also known for the widespread practice of vegetarianism in Indian society...

 dal
Dal
Dal is a preparation of pulses which have been stripped of their outer hulls and split. It also refers to the thick stew prepared from these, an important part of Indian, Nepali, Pakistani, Sri Lankan, and Bangladeshi cuisine...

 with rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...

, Middle Eastern
Middle Eastern cuisine
Middle-Eastern cuisine, West Asian cuisine, or in some place in the United States, Persian-Mediterranean cuisine is the cuisine of the various countries and peoples of the Middle East . The cuisine of the region is diverse while having a degree of homogeneity...

 hummus
Hummus
Hummus is high in iron and vitamin C and also has significant amounts of folate and vitamin B6. The chickpeas make it a good source of protein and dietary fiber; the tahini consists mostly of sesame seeds, which are an excellent source of the amino acid methionine, complementing the proteins in the...

, ful medames
Ful Medames
Fūl medammis , or simply fūl, is an Egyptian dish of cooked and mashed fava beans served with olive oil, chopped parsley, onion, garlic, and lemon juice. A staple meal in Egypt, it is popular in the cuisines of the Levant, Somalia, Eritrea, Ethiopia, Sudan and Saudi Arabia.-History:The roots of fūl...

, falafel
Falafel
Falafel is a deep-fried ball or patty made from ground chickpeas and/or fava beans. Falafel is usually served in a pita, which acts as a pocket, or wrapped in a flatbread known as lafa. The falafel balls are topped with salads, pickled vegetables, hot sauce, and drizzled with tahini-based sauces...

 with pita bread, the Mexican
Mexican cuisine
Mexican cuisine, a style of food that originates in Mexico, is known for its varied flavors, colourful decoration and variety of spices and ingredients, most of which are native to the country. The cuisine of Mexico has evolved through thousands of years of blending indigenous cultures, with later...

 beans with rice or tortilla
Tortilla
In Mexico and Central America, a tortilla is a type of thin, unleavened flat bread, made from finely ground maize...

 have arisen to provide complete protein
Complete protein
A complete protein is a source of protein that contains an adequate proportion of all nine of the essential amino acids necessary for the dietary needs of humans or other animals...

 in diets that are, by choice or by necessity, vegetarian
Vegetarianism
Vegetarianism encompasses the practice of following plant-based diets , with or without the inclusion of dairy products or eggs, and with the exclusion of meat...

. A food is considered to have sufficient lysine if it has at least 51 mg of lysine per gram of protein (so that the protein is 5.1% lysine).

Foods containing significant amounts of lysine include:
  • Catfish, channel, farmed, raw: 9.19% of the protein is lysine.
  • Chicken
    Chicken (food)
    Chicken is the most common type of poultry in the world, and is prepared as food in a wide variety of ways, varying by region and culture.- History :...

    , roasting, meat and skin, cooked, roasted: 8.11% of the protein is lysine.
  • Beef
    Beef
    Beef is the culinary name for meat from bovines, especially domestic cattle. Beef can be harvested from cows, bulls, heifers or steers. It is one of the principal meats used in the cuisine of the Middle East , Australia, Argentina, Brazil, Europe and the United States, and is also important in...

    , ground, 90% lean/10% fat, cooked: 8.31% of the protein is lysine.
  • Soybean
    Soybean
    The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...

    , mature seeds, raw: 7.42% of the protein is lysine.
  • Soybean
    Soybean
    The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...

    , mature seeds, sprouts
    Sprouts
    Sprouts may refer to:*Sprouting, the practice of germinating seeds, often for food purposes**Brussels sprouts, the most common meaning of the term in the United Kingdom**The sprouts of the mung bean, the most common meaning in the United States...

    : 5.74% of the protein is lysine (sprouting decreases the lysine content).
  • Winged Bean
    Winged bean
    The Winged bean , also known as the Goa bean and Asparagus Pea and Winged Pea, is a tropical legume plant native to New Guinea. It grows abundantly in hot, humid equatorial countries, from the Philippines and Indonesia to India, Burma, Thailand and Sri Lanka. It does well in humid tropics with high...

     (aka Goa Bean or Asparagus Pea), mature seeds, raw: 7.20% of the protein is lysine.
  • Lentil
    Lentil
    The lentil is an edible pulse. It is a bushy annual plant of the legume family, grown for its lens-shaped seeds...

    , pink, raw: 6.97% of the protein is lysine.
  • Lentil
    Lentil
    The lentil is an edible pulse. It is a bushy annual plant of the legume family, grown for its lens-shaped seeds...

    , sprouts
    Sprouts
    Sprouts may refer to:*Sprouting, the practice of germinating seeds, often for food purposes**Brussels sprouts, the most common meaning of the term in the United Kingdom**The sprouts of the mung bean, the most common meaning in the United States...

    , raw: 7.95% of the protein is lysine (sprouting increases the lysine content).
  • Parmesan cheese, grated: 7.75% of the protein is lysine.
  • Azuki bean
    Azuki bean
    The is an annual vine, Vigna angularis, widely grown throughout East Asia and the Himalayas for its small bean. The cultivars most familiar in north-east Asia have a uniform red color, but white, black, gray and variously mottled varieties are also known. Scientists presume Vigna angularis var...

     (adzuki beans), mature seeds, raw: 7.53% of the protein is lysine.
  • Milk
    Milk
    Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

    , non-fat: 7.48% of the protein is lysine.
  • Egg (food)
    Egg (food)
    Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...

    , whole, raw: 7.27% of the protein is lysine.
  • Pea
    Pea
    A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...

    , split, mature seeds, raw: 7.22% of the protein is lysine.
  • Kidney Bean, mature seeds, raw: 6.87% of the protein is lysine.
  • Chickpea
    Chickpea
    The chickpea is a legume of the family Fabaceae, subfamily Faboideae...

    , (garbanzo beans, bengal gram), mature seeds, raw: 6.69% of the protein is lysine.
  • Navy Bean, mature seeds, raw: 5.73% of the protein is lysine.
  • Amaranth
    Amaranth
    Amaranthus, collectively known as amaranth, is a cosmopolitan genus of herbs. Approximately 60 species are recognized, with inflorescences and foliage ranging from purple and red to gold...

    , grain, uncooked: 5.17% of the protein is lysine.

Properties


L-Lysine is a necessary building block for all protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 in the body. L-Lysine plays a major role in calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 absorption; building muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 protein; recovering from surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 or sports injuries; and the body's production of hormones, enzymes, and antibodies.

Modifications


Lysine can be modified through acetylation
Acetylation
Acetylation describes a reaction that introduces an acetyl functional group into a chemical compound...

, methylation
Methylation
In the chemical sciences, methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. Methylation is a form of alkylation with, to be specific, a methyl group, rather than a larger carbon chain, replacing a hydrogen atom...

, ubiquitination, sumoylation, neddylation
Neddylation
Neddylation is the process by which the ubiquitin like protein Nedd8 is conjugated to its target proteins. This process is analogous to ubiquitination, although relies on its own E1 and E2 enzymes...

, biotinylation
Biotinylation
In biochemistry, biotinylation is the process of covalently attaching biotin to a protein, nucleic acid or other molecule. Biotinylation is rapid, specific and is unlikely to perturb the natural function of the molecule due to the small size of biotin...

, pupylation, and carboxylation, which tends to modify the function of the protein of which the modified lysine residue(s) are a part.

Clinical significance


It has been suggested that lysine may be beneficial for those with herpes simplex infections. However, more research is needed to fully substantiate this claim. For more information, refer to Herpes simplex - Lysine.

Lysine has a known anxiolytic
Anxiolytic
An anxiolytic is a drug used for the treatment of anxiety, and its related psychological and physical symptoms...

 action through its effects on serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

 receptors in the intestinal tract. One study on rats showed that overstimulation of the 5-HT4 receptors in the gut are associated with anxiety-induced intestinal pathology. Lysine, acting as a serotonin antagonist
Antagonist
An antagonist is a character, group of characters, or institution, that represents the opposition against which the protagonist must contend...

 and therefore reducing the overactivity of these receptors, reduced signs of anxiety and anxiety-induced diarrhea in the sample population. Another study showed that lysine deficiency leads to a pathological increase in serotonin in the amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...

, a brain structure that is involved in emotional regulation and the stress response.

Human studies have also shown negative correlations between reduced lysine intake and anxiety. A population-based study in Syria included 93 families whose diet is primarily grain-based and therefore likely to be deficient in lysine. Fortification of grains with lysine was shown to reduce markers of anxiety, including cortisol levels, and also led to potentiation of benzodiazepine
Benzodiazepine
A benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...

 receptors (common targets of anxiolytic drugs such as Xanax and Ativan).

There are lysine conjugates that show promise in the treatment of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, by causing cancerous cells to destroy themselves when the drug is combined with the use of phototherapy
Light therapy
Light therapy or phototherapy consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light, usually controlled with various devices...

, while leaving non-cancerous cells unharmed.

While chemically insignificant to lysine itself, it is worth noting that lysine is attached to dextroamphetamine
Dextroamphetamine
Dextroamphetamine is a psychostimulant drug which is known to produce increased wakefulness and focus as well as decreased fatigue and decreased appetite....

 to form the prodrug
Prodrug
A prodrug is a pharmacological substance administered in an inactive form. Once administered, the prodrug is metabolised in vivo into an active metabolite, a process termed bioactivation. The rationale behind the use of a prodrug is generally for absorption, distribution, metabolism, and...

 lisdexamfetamine (Vyvanse). In the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

, the lysine molecule is cleaved from the dextroamphetamine, thereby making oral administration necessary.

According to animal studies, lysine deficiency causes immunodeficiency
Immunodeficiency
Immunodeficiency is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent. Immunodeficiency may also decrease cancer immunosurveillance. Most cases of immunodeficiency are acquired but some people are born with defects in their immune system,...

. One cause of relative lysine deficiency is cystinuria
Cystinuria
Cystinuria is an inherited autosomal recessive disease that is characterized by the formation of cystine stones in the kidneys, ureter, and bladder.-Signs and symptoms:Cystinuria is a cause of persistent kidney stones...

, where there is impaired hepatic resorption of basic, or positively charged amino acids, including lysine. The accompanying urinary cysteine results because the same deficient amino acid transporter is normally present in the kidney as well.

Limited studies suggest that a high-lysine diet or L-lysine monochloride supplements may have a moderating effect on blood pressure and the incidence of stroke.

Use of lysine in animal feed


Lysine production for animal feed is a major global industry, reaching in 2009 almost 700,000 tonnes for a market value of over €1.22 billion. Lysine is an important additive to animal feed because it is a limiting amino acid when optimizing the growth of certain animals such as pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s and chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...

s for the production of meat. Lysine supplementation allows for the use of lower-cost plant protein (maize
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...

, for instance, rather than soy) while maintaining high growth rates, and limiting the pollution from nitrogen excretion.

Lysine is industrially produced by microbial fermentation, from a base mainly of sugar. Genetic engineering research is actively pursuing bacterial strains to improve the efficiency of production and allow lysine to be made from other substrates.

In popular culture


The 1993 film Jurassic Park
Jurassic Park (film)
Jurassic Park is a 1993 American science fiction adventure film directed by Steven Spielberg. The film is based on the novel of the same name by Michael Crichton. It stars Sam Neill, Laura Dern, Jeff Goldblum, Richard Attenborough, Martin Ferrero, and Bob Peck...

, which is based on the 1990 Michael Crichton
Michael Crichton
John Michael Crichton , best known as Michael Crichton, was an American best-selling author, producer, director, and screenwriter, best known for his work in the science fiction, medical fiction, and thriller genres. His books have sold over 200 million copies worldwide, and many have been adapted...

 novel Jurassic Park, features dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s that were genetically altered
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...

 so that they could not produce lysine. This was known as the "lysine contingency," and was supposed to prevent the cloned
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...

 dinosaurs from surviving outside the park, forcing them to be dependent on lysine supplements provided by the park's veterinary staff. Most vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

s cannot produce lysine by default (it is an essential amino acid
Essential amino acid
An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism , and therefore must be supplied in the diet.-Essentiality vs. conditional essentiality in humans:...

).

In 1996, lysine became the focus of a price-fixing case
Lysine price-fixing conspiracy
The lysine price-fixing conspiracy was an organized effort during the mid-1990s to raise the price of the animal feed additive lysine. It involved five companies that had commercialized high-tech fermentation technologies, including American company Archer Daniels Midland , Japanese companies...

, the largest in United States history. The Archer Daniels Midland Company paid a fine of US$100 million, and three of its executives were convicted and served prison time. Also found guilty in the price-fixing case were two Japanese firms (Ajinomoto
Ajinomoto
Ajinomoto Co. Inc. , is a Japanese food and chemical corporation which produces seasonings, cooking oils, TV dinners, sweeteners, amino acids and pharmaceuticals...

, Kyowa Hakko) and a South Korean firm (Sewon). Secret video recordings of the conspirators fixing lysine's price can be found online or by requesting the video from the U.S. Department of Justice, Antitrust Division. This case served as the basis of the movie The Informant!, and a book of the same title.

See also

  • Acetyllysine
    Acetyllysine
    Acetyllysine is an acetyl-derivative of the amino acid lysine. There are multiple forms of acetyllysine - this article refers to N-ε-acetyl-L-lysine. The other form is N-α-acetyl-L-lysine....

  • Lysine price-fixing conspiracy
    Lysine price-fixing conspiracy
    The lysine price-fixing conspiracy was an organized effort during the mid-1990s to raise the price of the animal feed additive lysine. It involved five companies that had commercialized high-tech fermentation technologies, including American company Archer Daniels Midland , Japanese companies...

  • Deamination
    Deamination
    Deamination is the removal of an amine group from a molecule. Enzymes which catalyse this reaction are called deaminases.In the human body, deamination takes place primarily in the liver, however glutamate is also deaminated in the kidneys. Deamination is the process by which amino acids are...

  • Saccharopine
    Saccharopine
    Saccharopine is an intermediate in the metabolism of amino acid lysine. It is a precursor of lysine in the alpha-aminoadipate pathway which occurs in a few lower fungi, the higher fungi, and euglenids...


Sources

  • Much of the information in this article has been translated from German Wikipedia.