Isoleucine

(CC) Image: David E. Volk
Isoleucine, one of the common amino acids.

Isoleucine, abbreviated Ile or I, is one of the twenty common amino acids used by living organisms to build proteins. It is a nonpolar, uncharged, aliphatic and hydrophobic amino acid. In protein structures it is normally found in hydrophobic patches sequestered away from the protein surface. It is similar in structure and properties to the amino acids leucine and valine.