/uy'seuh looh"seen, -sin/, n. Biochem.a crystalline amino acid, C6H13O2, occurring in proteins, that is essential to the nutrition of humans and animals. Abbr.: Ile; Symbol: I[1900-05; ISO- + LEUCINE]
* * *One of the essential amino acids, present in most common proteins.It was first isolated in 1904 from fibrin, a protein involved in coagulation. It is used in medicine and biochemical research and as a nutritional supplement.
* * *an amino acid present in most common proteins, sometimes comprising 2 to 10 percent by weight. First isolated in 1904 from fibrin, a protein involved in blood-clot formation, isoleucine is one of several so-called essential amino acids for chicks, rats, and other higher animals, including man; i.e., they cannot synthesize it and require dietary sources. In microorganisms and plants, isoleucine is synthesized from the amino acid threonine.
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