- Only l-amino acids are found in proteins.
- Essential
- PVT TIM HaLL: Phenylalanine, Valine, Tyrosine, Threonine, Isoleucine, Methionine, Histidine, Leucine, Lysine.
- Glucogenic: Methionine, histidine, valine. I met his valentine, she is so sweet (glucogenic).
- Glucogenic/ketogenic: Isoleucine, phenylalanine, threonine, tyrosine.
- Ketogenic: Leucine, Lysine. The onLy pureLy ketogenic amino acids (supplemented in pyruvate dehydrogenase deficiency)
- Essential amino acids for low birth weight infants
- Cysteine, arginine, taurine
- Acidic
- Aspartic acid, glutamic acid.
- Negatively charged at body pH.
- Basic
- Arginine, histidine, lysine.
- Arginine is most basic. Histidine has no charge at body pH.
- Arginine and histidine are required during periods of growth.
- Arginine and lysine are ↑ in histones which bind negatively charged DNA.
- His lys (lies) are basic.
- Neutral
- Alanine, Serine, Threonine, Valine, Isoleucine, Leucin, Phenylalanine, Tyrosine, Tryptophan
- Found in urine in Hartnup disease
- Nonpolar
- Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Tryptophan, Methionine, Proline, Glycine
- Amino acid derivatives
- Methionine → cysteine, carnitine, taurine & lecithin
- Choline + acetyl-CoA (with enzyme choline acetyltransferase) → Acetylcholine
- Glutamine (with enzyme glutaminase) → Glutamate (with enzyme glutamate decarboxylase & Vitamin B6) → GABA
- Aromatic amino acids:
- Phenylalanine – benzene ring;
- Histidine – Imidazole ring;
- Tryptophan – Indole ring;
- Proline contains a ring structure, but is not classified as an aromatic amino acid