L-leucine is one of the three essential branched-chain amino acids (BCAAs) that is acquired from the diet. The catabolism of L-leucine occurs in the mitochondrion and involves several steps, including a transamination followed by a decarboxylation, which ultimately lead to the production of acetoacetate and acetyl-CoA. Acetyl-CoA can enter the tricarboxylic acid (TCA) cycle or be used for fatty acid biosynthesis, while acetoacetate is part of the ketone bodies metabolism. (Adapted from
PMID:30485760.)