Isoleucine

Some important facts about Isoleucine:
Isoleucine is an essential amino acid, only synthesized in plants and bacteria, and required in the diet by animals. In proteins, the hydrophobic isoleucine side-chain tends to reside with other hydrophobic residues in the interior of globular proteins or in transmembrane domains.
Isoleucine biosynthesis begins with the common metabolic intermediate pyruvate, the endpoint of glycolysis. The first step in isoleucine biosynthesis requires thiamine pyrophosphate to form a carbanion intermediate. Another component comes from the amino acid threonine, which is deaminated to produce alpha-ketobutyrate. Alpha-ketobutyrate and the TPP intermediate react to produce alpha-aceto-alpha-hydroxybutyrate that is isomerized, reduced and dehydrated to create alpha-keto-beta-methylvalerate. In the last step, valine aminotransferase transfers an amino group from glutamate to produce isoleucine.
1. The isoleucine pathway is almost the same as the valine biosynthesis pathway, using the same enzymes, and varying primarily at the first step in the pathway.
2. As a key enzyme in the synthesis of leucine, isoleucine and valine, acetolactate synthase is the target of several herbicides and mutation of this enzyme is responsible in some cases for the development of herbicide resistance.

Use of isoleucine:
1. It helps in the production of energy in the body and has been found experimentally to reduce twitching and tremors in animals.
2. It is also used as supplements for body (muscle) building.
3. Isoleucine, together with the other two branched-chain-amino-acids leucine and valine helps in the muscle recovery after physical exercise.
4. It is also needed for the formation of hemoglobin as well as assisting with regulation of blood sugar levels as well as energy levels. It is also involved in blood-clot formation.

Properties:
Isoleucine is a member of the branched-chain amino acid family. The three branched-chain amino acids - isoleucine, leucine, and valine - constitute approximately 70 percent of the amino acids in the body proteins. As such, their value in the formation and maintenance of structural and functional integrity in humans is unmeasured.
Amen and Yoshumira have presented evidence which indicates that isoleucine, leucine, and valine are important for stimulating anabolic function in humans. Isoleucine is also converted in the liver to blood sugar; therefore, it can be helpful in maintaining proper blood glucose levels. Therapeutic doses of isoleucine range between 200 and 2,000 mg per day.
1. Isoleucine (i's?lu'sen) , organic compound, one of the 20 amino acids commonly found in animal proteins. Only the L-stereoisomer appears in mammalian protein.
2. It is one of several essential amino acids needed in the diet; human beings cannot synthesize it from simpler metabolites. Young adults need about 20 mg of this amino acid per day per kg (or about 8 mg per lb) of body weight.
3. Isoleucine can be degraded into simpler compounds by the enzymes of the body. In a rare, inherited disorder called maple syrup urine disease, a nonfunctional enzyme in the common pathway of isoleucine, leucine, and valine degradation causes the buildup of certain metabolites in the urine, resulting in the characteristic odor from which the disease derives its name.
4. Once isoleucine is incorporated into protein, it contributes to the structure of protein by the tendency of its side chain (composed only of carbon and hydrogen) to seek an environment consisting of similar side chains, like those of leucine, valine, tryptophan, and phenylalanine, and to exclude water.
This hydrophobic property is analogous to that which prevents oil from dissolving in water. The tendency for these hydrophobic residues to associate with one another is evidently quite important in determining the bending and folding (tertiary structure) of the peptide chain characteristically seen in every protein. Isoleucine was isolated from beet sugar molasses in 1904.
1. Its chemical composition is identical to that of leucine, but the arrangement of its atoms is slightly different, resulting in different properties.
2. Nutritionally, in humans, isoleucine is an essential amino acid.
3. Isoleucine is a hydrophobic amino acid. Isoleucine has two chiral centers; therefore there are four possible stereoisomers of isoleucine and two possible diastereomers of L-isoleucine. However, isoleucine present in nature exists in one enantiomeric form, (2S,3S)-2-amino-3-methylpentanoic acid.

Deficiency symptoms of isoleucine:
Deficiency of isoleucine is found in people whose diet is deficient in dietary protein. The symptoms may include headaches, dizziness, fatigue, depression, confusion as well as irritability.
Symptoms of deficiency may resemble the symptoms of hypoglycemia. This nutrient has also been found to be deficient in people with mental and physical disorders, but it is not confirmed as yet.

Symptoms of high intake:
Higher intakes of isoleucine does not produce any harmful effects for most of people but those with kidney or liver disease should not consume high intakes of amino acids without medical advise.
People ingesting higher amounts of isoleucine report elevated urination.

When more may be required:
Athletes who are engaged in strenuous activity under extreme pressure and at high altitude require high intake of vitamin.

Method of Action:
An inborn error in isoleucine metabolism that effects a very small percentage of people can result in the buildup of metabolites in the urine, resulting in what is called "maple syrup urine disease". This condition can be evaluated in infants who may be susceptible to this genetic metabolism disorder. Isoleucine supplementation should not be applied to these individuals. Degradation of the branched-chain amino acids creates a series of branched fatty acid starter pieces, whose utilization leads to the formation of fatty acids that can be incorporated into complex phospholipids. The branched-chain amino acids have a unique muscle-sparing ability due to their gluconeogenic activity.
Daily requirement:
Foods high in isoleucine include:
· Cottage cheese (dry) 2,475 mg/cup
· Cottage cheese (crmd) 1,769 mg/cup
· Fish & other seafoods 4,000-6,000 mg/lb
· Meats 1,500-6,000 mg/lb
· Poultry 2,000-4,500 mg/lb
· Peanuts, roasted w skin 3,000 mg/cup
· Sesame seeds 2,000 mg/cup
· Dry, whole lentils 2,500 mg/cup