Isoleucine is an essential amino acid which surprisingly, cannot be synthesized by the human body; yet it is still required for bodily functions. Since our bodies can't make it, we have to ingest it; it is found in almonds, cashews, chicken, eggs, fish, lentils, liver, meat, etc.
Isoleucine is important for muscle recovery after exercise, synthesis of hemoglobin, regulating blood sugar levels and energy levels, and also is involved in forming blood clots. If there isn't enough isoleucine found in the body symptoms like dizziness, headaches, fatigue, depression, confusion, etc. may occur.
One neat fact about isoleucine is that when it is heated for decomposition, it emits toxic nitric oxide fumes which can be deadly.
The configuration of the chiral center that is on the left region of the molecule is R, whereas the configuration of the second chiral center is S.