Which of the following amino acids is purely ketogenic
Glucogenic amino acids: - These can be converted into glucose. 14 amino acids are glucogenic: alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, methionine, proline, serine, threonine, valine.
Ketogenic amino acids: - These can be converted into ketone bodies. These are leucine and lysine.
Both glucogenic and ketogenic amino acids: - These can be converted into both glucose and ketone bodies. These are isoleucine, phenylalanine, tyrosine, tryptophan.
Note: According to Harper 29th/e (P-282), lysine is both ketogenic and glucogenic. But all other textbooks have mentioned it as ketogenic.
Phenylalanine
Leucine
Proline
Tyrosine