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Sep 05,2008
Chemical Properties: Aliphatic (Aliphatic R-group)
Physical Properties: Nonpolar
Isoleucine, an essential amino acid, is one of the three amino acids having branched hydrocarbon side chains. It is usually interchangeable with leucine and occasionally with valine in proteins.
The side chains of these amino acids are not reactive and therefore not involved in any covalent chemistry in enzyme active centers.
However, these residues are critically important for ligand binding to proteins, and play central roles in protein stability. Note also that the β carbon of isoleucine is optically active, just as the β carbon of threonine. These two amino acids, isoleucine and threonine, have in common the fact that they have two chiral centers.
Isoleucine is an essential amino acid and is part of the three "branched chain amino acids" (BCAA) - the other two being leucine and valine. This amino acid cannot be manufactured in the body, and needs to be supplied in the diet and was first isolated in 1904 from fibrin.
Isoleucine is required for
Isoleucine, together with the other two branched-chain-amino-acids promote muscle recovery after physical exercise and on its own it is 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.
Deficiency of isoleucine
Deficiency of isoleucine is only found in people deficient in dietary protein but symptoms may include headaches, dizziness, fatigue, depression, confusion as well as irritability. Symptoms of deficiency may mimic the symptoms of hypoglycemia. This nutrient has also been found to be deficient in people with mental and physical disorders, but more research is required on this.
Also see leucine and valine, and look at branched-chain amino acids.
Dosage
The dosage listed is the Recommended Daily Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.
Most people ingest enough isoleucine from their diet, although some individuals do supplement their diet with about 650 - 700 mg of isoleucine per day (based on a 70 kg body), or worked out to 10 - 12 mg per kg of body weight per day.
If you are taking a supplement of isoleucine, keep it in balance with the other two branched-chain-amino-acids leucine and valine in the formula of 2 mg of leucine and valine for each 1 mg of isoleucine.
Toxicity and symptoms of high intake
Consuming higher amounts of isoleucine is not associated with any health risks for most 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
People involved with strenuous athletic activity under extreme pressure and high altitude may benefit from supplementation of this nutrient.
Food sources of isoleucine
It is present in almonds, cashews, chicken, eggs, fish, lentils, liver, meat etc.
- Protein synthesis and promoting anabolic effects, which is important for those who have intense exercise and athletic activities.
- Athletes who have increased protein requirements, but are on calorie restrictive programs.
- Reducing catabolism of muscles for bed-ridden patients.
- Post surgical patients - for tissue repair of muscles, as well as bone and skin.
- Helping to stabilize blood sugar and energy levels.
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