Valine, isoleucine and leucine, all essential amino acids, are the pyruvate family. Pyruvate is the source of 2 of the 6 carbon atoms of Isoleucine, and aspartate is the precursor of the other 4. Thereby, Isoleucine is also an aspartate family member.

Valine and isoleucine are both synthesized by the same five-step pathway, the only difference being in the first step of the series.

The leucine biosynthetic pathway branches off from the valine pathway at a-ketoisovalerate. The reactions from a-ketoisovalerate to a-ketoisocaproate are reminiscent of the first three reactions of the citric acid cycle. Here, acetyl-CoA condenses with a-ketoisovalerate, wich then undergoes a dehydration/hydration reaction, followed by oxidative decarboxylation and transamination, to yield leucine.

Pyruvate is the a-keto acid of alanine, so it's also precursor of alanine, yielding it by amidation(transamination), as in the cori cycle.