isoleucine

A nonpolar branched chain amino acid with the formula C₂H₅CH(CH₃)CH(NH₂)COOH. Isoleucine is synthesized from threonine. The pathway is similar to that for valine and leucine and many of the enzymes are common to all three. Degradation of isoleucine is also closely related to that of leucine and valine, leading to succinyl CoA. The final part of the degradation, from propionyl CoA, is common to valine, isoleucine, and methionine.