A ketogenic amino acid is an amino acid that can be degraded directly into Acetyl CoA through ketogenesis. This is in contrast to the glucogenic amino acids, which are converted into glucose. Ketogenic amino acids are unable to be converted to glucose as both carbon atoms in the ketone body are ultimately degraded to carbon dioxide in the citric acid cycle.
In humans, two amino acids are exclusively ketogenic:
- leucine
- lysine
In humans, five amino acids are both ketogenic and glucogenic:
- isoleucine
- phenylalanine
- tryptophan
- tyrosine
- threonine