Alloisoleucine Unit Converter

Alloisoleucine is a branched-chain amino acid and a stereoisomer (mirror-image form) of the essential amino acid isoleucine. It is produced in the body as a natural byproduct when isoleucine is broken down through a process called transamination.

In healthy individuals, alloisoleucine is present in plasma only in trace amounts (typically under 5 µmol/L). When levels rise above this threshold, it is considered a hallmark indicator of maple syrup urine disease (MSUD), a rare inherited metabolic disorder.

Alloisoleucine is typically measured alongside other branched-chain amino acids (leucine, isoleucine, and valine) as part of a quantitative plasma amino acid profile.

Alloisoleucine is formed inside the body as an unavoidable byproduct of isoleucine metabolism. During normal transamination of isoleucine, a small amount of racemization occurs at one of its carbon atoms, producing alloisoleucine through retransamination of the resulting intermediate.